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Dr. Joan Holt is the associate director of the Fisheries and Mariculture Lab at the University of Texas at Austin Marine Science Institute in Port Aransas. She’s done pioneering work in the field of marine aquaculture, and has helped launch a movement to change the way that fish are raised and sold for saltwater fish tanks.
Credit: Scott Holt
Marine biologists at The University of Texas at Austin Marine Science Institute are developing means to efficiently breed saltwater aquarium fish, seahorses, plankton and invertebrates in captivity in order to preserve the biologically rich ecosystems of the world’s coral reefs.
These scientists believe their efforts, and those of colleagues around the world, could help shift much of the $1 billion marine ornamental industry toward entrepreneurs who are working sustainably to raise fish for the aquarium trade.
“It’s the kind of thing that could transform the industry in the way that the idea of ‘organic’ has changed the way people grow and buy fruits and vegetables,” says Joan Holt, professor and associate chair of marine science at The University of Texas at Austin. “We want enthusiasts to be able to stock their saltwater tanks with sustainably-raised, coral-safe species.”
Holt is a co-author of a recent article, “Advances in Breeding and Rearing Marine Ornamentals,” published in the Journal of the World Aquaculture Society in April.
The paper is a complement to Holt’s broad-ranging work over the past 10 years to promote captive breeding of ornamentals. She’s been a pioneer in developing food sources and tank designs that enable fragile larvae to survive to adulthood.
Holt has also been a vocal critic of the extraordinarily wasteful methods currently used to bring sea creatures from the oceans to the tanks.
“One popular method is to use a cyanide solution,” says Holt. “It’s squirted into the holes and crevices of the reef and it anesthetizes the fish. They float to the surface. Then the collectors can just scoop them up, and the ones that wake up are shipped out.”
This method, says Holt, has a number of unfortunate effects. It bleaches the coral. It kills or harms other species that make the coral their home, particularly those that can’t swim away from the cyanide. It can deplete or distort the native populations of the species. And it contributes to 80 percent of traded animals dying before ever reaching a tank.
Unlike the freshwater ornamental market, which relies mostly on fish raised in captivity, the saltwater ornamental market is 99.9 percent wild caught. Holt says this is largely because there’s less accumulated knowledge on breeding saltwater fish in captivity. Saltwater species also tend to spawn smaller, less robust larvae, which are harder to rear to maturity, and to rely on various foods, such as plankton, that are not readily available in mass quantities for breeders.
Yet all these difficulties, says Holt, are surmountable.
She and her colleagues in Port Aransas, where the Marine Science Institute is located, have successfully bred in captivity seven species of fish, seahorses and shrimp they’ve caught from the Gulf of Mexico and the Caribbean, including species that other biologists had tried but failed to rear before. Others have successfully bred popular species like clownfish, gobies, dottybacks, and dragonets, as well as coral, clams, invertebrates, and algae.
Several big aquariums, including SeaWorld, have committed to assisting in the breeding and egg collection effort, and to integrating into their exhibits information about how the aquarium trade impacts the coral reefs.
Holt and her colleagues envision, ultimately, is a “coral-safe” movement. The science, the economics and the social awareness could together result in a sea change in how saltwater aquariums are populated and how saltwater tank enthusiasts think of themselves and their passion.
As more tank-raised ornamentals percolate into the market, Holt believes people will see another advantage to buying sustainably. The fish will simply do better. They’ll live longer, be healthier and be easier to care for.
“Species that are bred in captivity should adapt much better to your tank than something that was just caught halfway across the world, in a different system,” says Holt. “Good retailers will want to sell these species, and consumers will benefit from buying them.”
Source: University of Texas at Austin
By Mike Hellweg
As promised, I spent some time in a couple of local big box stores and a couple of local fish stores. In both big box stores the pickings were mighty slim for me— mostly big fish like cichlids. But there were a few nice small fish from which I selected some potential breeding stock.
The local fish stores were even better. I was able to go into one and find several pairs of tetras and barbs that were old enough for spawning. Even better, in one I was able to get them all on sale at a huge discount! And in the other, I was able to trade a bunch of young fish from the contest for several pairs and a couple of breeding groups that were almost ready to go. This illustrates one of the great reasons to support your local shop—I was able to trade in some of my breeders to one local shop and get a couple more species in exchange.
So in a couple of hours, with a couple of stops, spending only about $25, I re-homed a large number of fish and brought home enough fish to keep me busy for at least a couple of weeks in the contest.
Obviously, all of the fish, even those I get from friends, go into quarantine first. No sense introducing disease into an established tank.
Here are some of the fish I found:
Livebearers and Killies:
Wild-type green swordtails Xiphophorus hellerii
Coral red platies Xiphophorus sp. domestic platy
Sunset variatus Xiphophorus sp. domestic variatus
Corydoras narcissus (marked as skunk cories – Corydoras arcuatus)
Pearl danio Danio albolineatus – these were on sale for just 11 cents each!
Zebra danio Danio rerio – 11 cents each!
Blue danio Danio sp. – 11 cents each!
Fireline danio Devario sondhi
Black skirt tetra Gymnocorymbus ternetzi
Silvertip tetra Hasemania nana
Glowlight tetra Hemigrammus erythrozonus
Head and tail light tetra Hemigrammus ocellifer
Pretty tetra Hemigrammus pulcher
Ember tetra Hyphessobrycon amandae
Columbian redfin blue tetra Hyphessobrycon columbianus
Sickle fin tetra Hyphessobrycon robertsi
Serpae tetra Hyphessobrycon serpae
Neon tetra Paracheirodon innesi
Tiger barb Puntius anchisporus
Melon barb Puntius melanampyx
Black ruby barb Puntius nigrofasciatus
Gold barb Puntius semifasciolatus or Puntius “sachsi”
White cloud mountain minnow Tanichthys albonubes
Penguin tetras Thayeria obliqua
Honey gouramis Colisa chuna
Pearl gouramis Trichogaster leeri
Gold gouramis Trichogaster trichopterus
Tank Raised Bangaii Cardinals Pterapogon kauderni
And a group of spotted loaches – no idea what species they are but they are easily sexable, so I’ll keep my fingers crossed!
Since Ted mentions it, I’ll stress again how important quarantine is to success with aquarium fish. Several of the neon tetras and fireline danios came down with ich soon after arriving home. It is likely the cold weather somewhere in transit, either at the airport here before they made it to the shop, or in the delivery truck stressed them and made them susceptible. Fortunately, I followed my normal procedure and put the new fish in quarantine tanks. The ich only affected two of those tanks. I was able to treat it immediately since I was watching for it, and only lost a couple of fish. The rest came through with flying colors. Of course this sets any breeding attempts with those two species back several weeks as they will need time to recover. But I’ve got plenty of fish to work with for the next few weeks.
Neolamprologus pulcher. Photograph from TFH Archives.
By David E. Boruchowitz
Cichlids demonstrate extremely sophisticated reproductive strategies. One of the least common involves cooperative breeding in groups or colonies. Lake Tanganyikan Neolamprologus pulcher breed en masse, with the entire colony rising as one to fend off predators, and with non breeding individuals participating in the care and protection of the offspring.
Aquarists have long known about this behavior, which is more obvious in the wild, where hundreds of fish are involved, but which translates in captivity into breeding groups that avoid the typical predation on the fry by non parental adults in the same tank.
A new study reveals that about 10 percent of the fry produced in these colonies are sired by subordinate males, and that those males are more diligent in protecting the young.
This is reminiscent of the situation in several Xiphophorus swordtails, where smaller, inconspicuous males rely on sneaking rather than courtship to father a small percentage of fry. In both cases subordinate males father a small but significant number of offspring, though in the case of the swordtails it is a matter of genetic castes among the males, not just one of dominance.
By Ted Judy
Twenty years ago I kept and bred a lot of Lake Malawi cichlids. It is hard to beat the riot of color in a well-stocked Malawi community. Matthew (my 7-year-old fish fanatic in the making) discovered this colorful genre about a year ago, and has been slowly taking over tank space in the house ever since. We are up to three Malawi community tanks: a 42-gallon bow front in Matthew’s room, a 55-gallon in the family room, and a 40-gallon breeder in the fish room. I decided to take advantage of these three tanks for the contest by converting the tanks from purely aesthetic communities into breeding colonies.
What is the difference between a community and a breeding colony? A community can be any mix of fish regardless of sex ratio, age and compatibility (though I would hope they all can get along). A breeding colony is a group of fish set up to encourage breeding. There is some cross over. Purists and serious breeders will usually set up single-species colonies with only one or two males and many females. These large colonies will usually produce a lot of fry, but only of one species. Matthew and I chose to sacrifice large numbers of fry in hopes of getting multiple species to breed in the same tank.
The trick is to set up groups of fish that are compatible, but are not so similar that hybridization is likely to occur. Luckily there are so many different Lake Malawi cichlids that finding a good mix is not too hard to do. The two main breeding tanks are the 42-gallon bow front and the 55-gallon. The 40-breeder in the fish room has one species old enough to spawn (Labeotropheus trewavasae “Mphanga”) and a bunch of young fish that are growing up to be the next groups to go into the spawning tanks.
Labeotropheus trewavasae “Mphanga.”
The 42-gallon tank has a quad (one male and three females) of adult Aulonacara stuartgranti ‘Ngara’ peacocks, a trio of Metriaclima sp. “white top Hara” and a trio of the electric blue “johanni” Melanochromis cyaneorhabdos. We had to get rid of a few single males of different species and find some females to fill out the colonies. We also added a lot more hiding places, which we did very inexpensively by asking the local plant nursery for any large damaged flower pots. Matthew is very good at getting free broken pots, which we broke more until they would fit in the tank. A big pile of the curving terra cotta pieces is perfect for these cichlids.
Aulonacara stuartgranti “Ngara.”
The 55-gallon has a quad of large OB Labeotropheus fuellebourni, a group of eight (two males, six females) Metriaclima sp. “Msobo,” and a trio of Pseudotropheus sp. “red cheek.” I am a little concerned about hybridization between the Pseudotropheus and Metriaclima, but I have not seen any evidence of it happening. In my experience, if there are suitable mates of the same species for all the fish in the tank hybrid breeding rarely occurs. I will hope for the best and pay careful attention to the fry.
Labeotropheus fuellebourni; offering a suitable number of mates of the same species is often a good way to prevent hybridization.
Metriaclima sp. “Msobo”; pay careful attention to the colors and patterns on the fry to check that hybridization has not occurred.
The colonies were set up before the contest started, but we only had one species spawn right away: Metriaclima sp. “Msobo.” Nothing else spawned in the next two months. I started feeding more heavily and doing large water changes more frequently. Once every two weeks I would do a really large water change followed by a 4-day fast. Sometimes the lack of the diversion of food will trigger fish to spawn. The weather started to get cooler, and that is not conducive to getting Malawi fish to breed, so I was worried that I would not see any success until spring. So the first week of December I added a big heater to each tank and jumped the temperature up to 82F in hopes of heading off a winter lull. I normally do not keep my tanks much above 74F. I believe that cooler water is better for the health of the fish (assuming the fish are not ‘hot water’ species). I also went out onto my local club’s forum and asked for advice. Everyone said to split the communities up and go back to one species per tank.
I was about to do that when everything started to spawn. Within three days we had holding females of the L. trewavasae “Mphanga,” L. feullebourni, A. stuartgranti “Ngara,” Melanochromis cyaneorhabdos, and Metriaclima sp. “white top Hara.” Five out of seven is not bad, and since the M. sp. “Msobo” spawned early in the competition we are left with only one species of breeding-age Malawi cichlid to spawn.
The plan now is to rotate the species that have spawned out and new species in. Matthew is excited… he LOVES to shop for fish (the apple does not fall far from the tree).
By Ted Judy
There are many species of tetras, barbs and danios that are not difficult to spawn. A good rule of thumb to figuring out a species’ difficulty is to compare prices at a fish store. Fish that are common and inexpensive are most often farm raised and easy to breed. The poster-fish for this group is the zebra danio Danio rerio. There are two challenges for the hobbyist breeder when working with these species. First, collecting the eggs can be impossible if the breeding tank is not set up to catch eggs. Second, raising the very small fry can be a challenge without the right foods ready when they are needed.
I breed most of the tetras, barbs and danios in 2.5 gallon tank. When the fish are very small, and lay a lot of eggs, I usually put a lot of yarn mops in the tanks. After a few days the fish have deposited plenty of eggs in the yarn. Some will get eaten, but there are enough hidden in the mops to meet my modest requirements (I do not really need or want more than a dozen fry). Larger species tend to be better at eating their eggs, so I use a false bottom in the tank made from a piece of plastic needle-point mesh cut to fit into the 2.5-gallon tank. I cut the screen so that it drapes in the bottom. I use a couple pieces of PVC to hold the plastic off of the glass.
A spawning mops hides the eggs from the parents so they do not get eaten.
Creating a false bottom using a screen is another way to separate parents from their eggs, and works best with larger species that tend to eat eggs off the spawning mop.
Once the screen is in place I add plants or yarn as a place for the fish to spawn. The eggs filter through the plants and then fall through the plastic mesh. Since the bottom of the tank is bare the eggs easily seen. After the eggs are laid I remove the fish, screen and pvc. I leave the plants and add a drop or two of methylene blue. I cover the top of the tank with a piece of cardboard to block the light. Most species’ eggs hatch in less than three days, and the fry are ready to eat a day later.
The first food I use is paramecium. If you do not have a paramecium culture there are products on the market, called fry foods, which are designed to provide small particles for baby fish. A good supplement to a food product is ‘sponge grunge’. Squeeze a well established sponge filter into the tank with the fry and some plants. The microorganisms in the sponge will start a colony that will feed to fry. After a few days the fry can eat microworms. One trick I use is to keep my microworm cultures very wet, about the consistency of a thick soup. The media in the culture contains all different sizes of the nematodes. When I feed from the culture, I scoop a little of the media onto my finger and swirl it into the tank with the fry. Yes, it clouds the water… but the fry do not care, and they are getting very small food.
After a week most fry can eat baby brine shrimp and they are off to the races. With lots of food and frequent water changes they will grow fast.
I have ten 2.5-gallon breeding tanks in my fish room. From spawn to relocating the fry to a growout tank tanks about 10 – 15 days. If everything works out perfectly I could breed 20 – 30 species of ‘easy’ tetras, barbs and danios in thirty days. Plans rarely work out perfectly, however, and I am happy to be successful with 5 – 10 successful spawns each month.
By Mike Hellweg
Fish will do what comes naturally and spawn in our aquaria IF we give them what they need. With many species that means approximating the spawning season, giving the adults what barb and tetra guru Randy Carey calls a “trigger” to initiate spawning. Following the metaphor, all we as aquarists need to do is figure out how to turn off the safety and pull the trigger.
With many fish like cichlids and livebearers, all we have to do is buy a group of juveniles and grow them out. Eventually, they will reach sexual maturity and pair off, even in a community tank. Often they will even successfully raise a brood of fry in that same community tank. But many other fish aren’t so easy. Many of them require a little to a lot of extra work on the part of the hobbyist.
Blackworms are an excellent live food to use to help induce spawning in somewhat difficult fish.
With these fish it is best to separate out the males from the females. When you have limited tank space, the best way to do this is to move the female(s) to what will become the spawning tank, and leave the male(s) in the community tank.
At first the spawning tank can have water similar to the main tank. As the conditioning period goes forward, begin changing the water out with water more appropriate for the particular species (harder, softer, more basic or acidic, more or less salty, etc.). Do several water changes over the course of a week to 10 days.
Feed the adults heavily with meaty foods. Flake or pellet food just isn’t enough. There are various enzymes, amino acids, and other things in living foods that are destroyed by processing. This is why every experienced breeder will tell you that you need to use live foods for conditioning. Many of us use frozen and freeze-dried foods as well, but live foods really provide that extra boost that makes the difference between success and failure.
European drift worms are another type of worm that can be cultured and fed to fish that are being conditioned to breed.
Every time I give a talk on breeding fish, I quote my friend and breeding guru Charley Grimes of Indianapolis. I think he put it most succinctly: “the best way to put eggs in her belly is to put worms in her tummy.”
Worms are an excellent live food. We are fortunate in that we have many different types of worms to use that can be sized to the mouth of the fish, or larger worms can be cut up for feeding smaller fish. Some of the ones currently in use by breeders include Grindal worms, white worms, tubifex worms, Dero worms, black worms, red wigglers, European drift worms, and night crawlers. All can be found in a local pet shop or bait store, or they can usually order them for you. If not, members of a local aquarium or herp club likely can supply starter cultures and information on how to culture them. Or you can go to various sites on the web and order them from reputable growers. Of course, you can also read my book Culturing Live Foods (T.F.H. Publications, 2008) for tips on starting many different types of live food cultures.
Whiteworms do best at cooler temperatures, which is why these are stored in a fridge.
Live food cultures need to be fed. Here whiteworms are eating a slice of bread.
Most breeders culture their own live foods. There is a lot of excellent information out there about culturing live foods, including several excellent books. Culturing your own foods gives you a chance to control every aspect of your fish’s diet. More on this later…
By Mike Hellweg
When Ted first approached me with the idea for this contest, I jumped at the chance to help promote my favorite part of the hobby, breeding fish. I knew I would have to step up my game a bit (Ted is a fierce competitor!), but that also would require some modifications to my fishroom.
First, I needed to have a place for all of the fry to grow out. After all, if I was going to participate in this contest, I would also want to support my own club (the Missouri Aquarium Society, Inc. [MASI]) in our Breeders Award Program (BAP). But that would mean holding the fry for 60 days. I know, our contest rules include growing them out to 30 days, which is generally the safe point from which you know the fry will survive, but my club requires them to be at least 60 days old. That means I have to tie up tanks for twice as long as Ted. But it also means my fry will be closer to saleable size when I turn them in, so I can get them to local shops at this time, too.
I know some readers will want to know more about my fishroom. It is approximately 12 feet by 14 feet. In the walls and ceiling I installed R-30 insulation to cut down on heating and cooling costs. It is heated and cooled with our home’s central air and heating. This means I don’t have to worry too much about temperature control in individual tanks. For electrical supply in the room, I added three extra ground fault circuit interrupters (GFCI) protected circuits just for the fishroom. One is on a timer and runs the lights, another is on all the time and is for any extra filters/heaters that I might need, and the third is extra, in case I want to run something extra at some point. All of the tanks are filtered with air driven sponge filters powered by a linear piston air pump, and all of them contain live plants.
All of the tanks are drilled with overflows that go to a floor drain, so water changes are easy; I just run a hose from my 220 gallon water holding system to each tank for a few minutes and let the old water flow into the drain. This system consists of four 55 gallon drums plumbed together. The water is treated, heated, aerated and circulated between the drums until needed. If a tank needs a bit more cleaning, I can drain individual tanks into a line that runs around the room and goes to the floor drain. I can also add hang on filters if needed, but I only use these when I need to clean a tank. Lighting is supplied by power compact florescent lights and by low power consumption commercial shoplights. To control humidity and prevent mold growth, I also added an exhaust fan that turns on automatically when the room humidity gets above 50%. This just dumps the humid air to the outside, and pulls in fresh, conditioned air from the rest of the house.
In my fishroom, I have a dozen 30-gallon breeders. Those are excellent grow out tanks, each will hold dozens or even hundreds of fry, depending on the species. I can even grow out fry of several species in one tank, if they are compatible in size and temperament. But even so, that means I can only grow out a dozen or so species at a time. I need more room. Fortunately, I have eight more 30-gallon “box” tanks from a local wholesaler that went out of business a few years ago that have just been sitting there, waiting for me to come up with something to do with them. They are called “box” tanks because they are shaped like a fish box – just a bit larger – two foot square and just under a foot deep. They are used in the trade to hold a box of fish each. With their large surface area and shallow depth, they can be stacked four high in the fishroom. This rack of tanks will only take up 8 square feet of floor space while giving me 32 square feet of tank floor space! This is perfect for my fishroom, where space is at a premium. So I begin this month setting up this rack up and starting to get these tanks ready to go.
Mike’s newest addition to his fishroom, a rack for more 30-gallon breeder tanks.
I also started conditioning fish for spawning. That means tanks for males and tanks for females in many species. I have a rack that holds 5 x 10 gallon tanks and 8 x 20 gallon “high” tanks that I designed for this purpose. It will also give me extra room to isolate new fish (every fish, invert, and new plant coming into my fishroom gets at least one month’s quarantine) and rotate extra pairs in case I have to separate fish from the main pairs in the breeding tanks.
With other fish, conditioning just means setting up a tank with proper conditions and feeding them well, while letting nature take its course. I have a wall of tanks set up just for this – a 30 long, 6 x 29 gallon tanks, 6 x 20 longs, 7 x 10 gallon tanks and 3 x 5 gallon cubes. These will be used for most of my breeding attempts.
I have a set of extra grow out tanks in case things get out of hand and I get lucky with spawnings. This consists of 4 x ½ ten gallon tanks (a specially made tank), 5 x 10 gallon tanks, 2 x 20 flats (made from two ten gallon tanks glued together – one with the back out and the other with the front out), and two fifty gallon flats (essentially a 75 gallon tank cut down to a foot deep). In addition, outside of the fishroom I have setups for larger fish. I have 7 forty breeders, a 58 breeder, and two 75’s.
A mated pair of Honduran Red Points Amititlania siquia in Mike’s fishroom.
Finally, the last group of tanks will be my “secret weapon” that I plan to roll out in month two or month three. More on that later – I don’t want to give too much away to Ted!
MELBOURNE, Victoria — After studying male desert goby fish, a team of Monash researchers has suggested that male sexual behavior is primed to produce the greatest number of offspring.
In the underwater world of desert goby fish, it is the males whose work is never done.
As exclusive parental guardians it is up to males to guard and fan the eggs – keeping them well-oxygenated and removing debris – while females flit about finding new mates.
Photo:P. Andreas Svensson.
Ted Judy, in a moment of utter foolishness, challenged Mike Hellweg to a one-on-one fish breeding contest. The rules are simple: spawn fish, raise the fry to an age when they can be safely given to another hobbyist, and repeat. The species that are spawned will be assigned point values based on the system used by the Missouri Aquarium Society, Inc.’s (MASI) Breeders Award Program (BAP), which ranks fish based upon their breeding difficulty.
The contest is to span one year, beginning with the January 2010 issue of TFH and ending with the December 2010 issue. Ted and Mike will submit a spawning report to TFH each month, as well as talk about the strategies, successes, and failures they experience during the competition. Our intrepid breeders will also update a blog at www.tfhmagazine.com/blogs so readers can get more frequent updates on what is going on in Mike’s and Ted’s fishrooms. TFH recently sat down with these master breeders to get some information about the contest, and learn a little more about the contestants:
Posted November 18th, 2009. Add a comment