Top of the Food Chain: Experiences with Cichla temensis
Author: Brian M. Scott
Cichla is the genus that the family Cichlidae was based on, and thus it serves as a flagship for the group. Ironically, biologists knew very little about this primitive genus in comparison to other more commonly studied genera (i.e., Metriaclima, Pterophyllum, Symphysodon, Apistogramma, and Cryptoheros) even though the family as a whole is shrouded in controversy and debate. One species, Cichla temensis, is the focus of this month’s column.
Cichla temensis was described in 1821 by F. H. A. von Humboldt, a well-known explorer and naturalist, in the famous paper co-authored by A. Valenciennes: “Recherches sur les poissons fluviatiles de l’AmÉrique Équinoxiale” (In Voyage de Humboldt et Bonpland, DeuxiÈme partie. Observations de Zoologie et d’Anatomie comparÉ).
Named after the type-locality river, the Rio Temi in Venezuela, C. temensis is one of the most distinguishable species of the genus. Until recently, the distribution of this fish was thought to be far more expansive. However, a recent paper by Dr. Sven Kullander and E. J. G. Ferreira, “A review of the South American cichlid genus Cichla, with descriptions of nine new species,” clarifies the true distribution of the species.
Naturally occurring populations of C. temensis are restricted to the Orinoco River Basin in the drainages of the Rio Orinoco in Venezuela and Colombia, and the Amazon River Basin in the drainages of the Rio Negro and Rio UatumÃ. The species has been introduced elsewhere, including southern Florida and Texas, but it is not established in either locality. However, Lake Guri, Venezuela, is home to a large population of well-established introduced C. temensis. Localities in Brazil, which were thought to have introduced populations of C. temensis, are actually invaded with its close cousin C. pinima, and perhaps C. vazzoleri.
The availability of C. temensis to hobbyists is very sporadic. Since they are a food and sport fish in Brazil, Venezuela, and Colombia, they are only allowed to be collected and exported by special permit and in limited numbers. Therefore, obtaining a “true” C. temensis, which is also wild collected, is somewhat tricky and can be an insanely frustrating feat. So it’s wise to take advantage if given the chance, but it will often be an expensive investment.
Many of the farm-bred specimens of C. temensis, commonly made available to hobbyists through fish farms in Asia, are actually hybrids of C. temensis and other species of Cichla (i.e., C. monoculus). It is often difficult to identify hybrids due to the dominant appearances of C. temensis, which tend to overshadow the traits shown by other Cichla when hybridization occurs. Those of you who have been interested in Cichla since the early 1990s may remember the different “look” the true species from these farms had back then—more elongated bodies, unbroken bars, sharper heads, clearer eyes (as opposed to red/orange eyes today), and a faster growth rate. These are all attributes of pure C. temensis.
With an average adult size of more than 24 inches in total length (TL), it should be of little surprise that C. temensis need huge aquariums. A single mature specimen, which is approximately 16 inches TL at 12 to 14 months of age, should be housed in an aquarium at least 24 inches wide and as long as possible, and as the fish grows, the size of the aquarium will need to increase dramatically.
Often, extremely dedicated hobbyists will have two or three specimens in tanks that measure 8 or 10 feet in length and 3 or even 4 feet in width. Height does not matter much, as the tank can never be deep enough to prevent C. temensis from trying to knock the lids off of it anyway! Generally speaking though, an aquarium of 24 inches in height is a good start, and one that is 36 inches tall would be better. Regardless, it’s the length and width of the aquarium that matters most.
Cichla can be belligerent fishes, and C. temensis is one of the most aggressive of the group. However, as juveniles they are more likely to be bullied rather than do the bullying themselves. For this reason, most keepers tend to keep C. temensis alone in species-specific aquariums.
C. temensis can certainly be kept in community settings as long as care is taken to choose their tankmates carefully. Of course, since Cichla have large mouths, their tankmates should be large enough so as not to become a meal. On the other hand, even though C. temensis have huge mouths, they are often picked on by even more belligerent fishes, such as those of the “Cichlasoma” complex (i.e., Nandopsis, Chuco, Amphilophus, and Parachromis).
Aside from the aggression and the possibility of tankmates becoming a meal, hobbyists should be aware of the swimming room that is required by these large cichlids. Cichla, in general, are active swimmers that hunt down prey visually. In nature they patrol the shallows during daylight hours, usually in the dawn and dusk (crepuscular) hours. Cichla are very powerful, efficient piscivorous predators that require large aquariums and must be provided with lots of swimming room if they are to be expected to thrive in captivity.
Diet and Feeding
C. temensis is a strict carnivore, though more appropriately classified as a piscivore, a.k.a. fish-eater. Wild-collected specimens will need small live fishes offered daily or every other day. Sub-adults and adults can be fed less frequently but should still be fed at least twice a week at minimum.
Even though C. temensis grows to tankbusting proportions, their diet consists of comparatively small foodstuffs. In nature, most of the fishes that C. temensis feeds on are characins, a family of fishes to which such venerable species as the black and redbelly piranhas belong, as do the peaceful cardinal and neon tetras, as well as many other fishes.
In aquariums, the feeding of live fish is somewhat of a controversial topic, and there are very few species that absolutely require live fish as food in order to survive. There is no doubt that fish sold as feeders are often in terrible health and have the ability to transmit diseases to your show fish. Fish eating fish, however, is a perfectly natural thing. If you have no objection to the practice, and if you have a good source for reliably clean and healthy feeder fish, then your fish can benefit from this natural food.
In addition to live fish, the use of a high-quality pellet diet is highly recommended. By using a pellet food, it is easier to provide a well-balanced diet to C. temensis, and other piscivorous fishes. There are many good types of pelleted foods available at most local pet shops. Additionally, many more are available through specialized sellers online or by special order. Pellets that are high in beta-carotenes and omega fatty acids are best for color enhancement. Those high in algae and kelp are used to add a touch of plant matter to the diet, which is beneficial for all predatory fishes. Pellets marketed for trout farming and the like all make excellent dietary supplements for C. temensis. Also, several popular brands of fish foods offer jumbo-sized pellets and floating food sticks, which work equally well.
Other types of foods, such as earthworms, crayfish, and seafood (i.e., shrimp, squid, clam, and chunked fish flesh) work well, too, and should be systematically employed in the dietary regimen. Shrimp, especially krill, provide color enhancement for C. temensis. Many aquarium-kept specimens have developed strikingly beautiful coloration when these foods have been incorporated into their diet on a regular basis.
Often, getting wild-collected Cichla to accept non-living foods is tricky, and it will take some time to get them used to the idea. One technique that seems to work with some degree of success, at least for juveniles, is to make sure the fish are eating well right from the start. Then withhold food for a few days. After two or three days with no food offerings, add a few small dead feeder fish so that the feeders are blown into the tank via the filter return.
Usually the Cichla will swallow the fish without any hesitation. Let a few hours pass and repeat the same scenario. Do this again for a day or so, but slowly add some pre-soaked pellets or small bits of seafood to the mix. After a while, usually a short while, the Cichla will immediately swallow anything that is offered via the filter return. Once the Cichla are actively feeding for a few days, food can be offered in the more normal way in the front of the aquarium. If the Cichla show any signs of reverting back to live food only, simply withhold food for a few days again and start the process over. Chances are they will not need a second feeding lesson, however.
C. temensis should be fed until their bellies are slightly rounded out (to satiation), but never to the point where they look completely distended. With juveniles, this should be done daily or at least every other day. Sub-adults and adults can be fed to satiation two or three times weekly.
Unlike many other cichlids, Cichla are picky about certain water parameters. They are particularly fussy about dissolved metabolites in their aquarium water. Additionally, the pH, hardness, and alkalinity are not crucial, but it’s best if extremes are avoided. Nitrogen compounds (i.e., ammonia, nitrite, and nitrate) are best maintained at levels as close to zero as possible.
The best way to maintain a stable, healthy environment for C. temensis is through regular partial water changes. Weekly or bi-weekly water changes are preferred, but monthly water changes are better than none at all. It’s important to maintain the proper temperature while performing water changes with Cichla. Since they are a warm-water-loving species, they need temperatures in the upper 70s to low 80s Fahrenheit for daily maintenance, and slightly elevated temperatures for breeding, disease control, and treatment.
C. temensis is capable of being housed with many species of fishes. However, while it is true that they will prefer to consume fishes much smaller than themselves, C. temensis are perfectly capable of swallowing others about one-third their size. That said, make sure that any potential tankmates are at least half of the size of your C. temensis (two-thirds their size is even better).
Some potentially good tankmates for inclusion in a tank with C. temensis are various silver dollar species of the genera Myleus and Metynnis, pacu Colossoma, tinfoil barbs Barbonymus schwanenfeldii, Satanoperca spp., Tilapia spp., waroo Uaru spp., oscars Astronotus spp., and of course other Cichla.
Unique and Fascinating Fish
C. temensis makes a fascinating fish for the home aquarium as long as a large tank is provided and the water quality is kept in good standing. They exhibit unique and interesting behavior; this can be similar to the dog-like antics of oscars, since they have the ability to recognize their caretakers, which is made obvious by their excited tail thrashing and other gestures. Tankmates can be tricky, but there are many that are acceptable, as long as their general size and aggression are taken into account. As long as these conditions are met, hobbyists should do quite well withthis exciting tankbuster.
See the full article on TFH Digital http://www.tfhdigital.com/tfh/200711/#pg62