Thinking Outside the Glass Box: Cracking the “Acuticeps” Code (Cichlidophiles)Author: Wayne S. Leibel
Thinking Outside the Glass Box: Cracking the “Acuticeps” Code (Cichlidophiles)
In last month’s column (TFH July 2007), I began what will be a multi-column discussion by example of how to spawn the unspawnable cichlid. In a nutshell, to spawn any fish, we must create conditions that approximate those experienced by the fish in the wild.
Some fish are adaptable and undemanding—convict cichlids, for instance. These “easy” beginner’s cichlid will spawn under virtually any conditions including, I am convinced, on wet grass if that is all that is available! And they ripen easily on a diet of commercial flake food, far different from their usual fare in the wild. Indeed, they are easy, and a useful starting point for budding cichlidophiles!
Other cichlid species, the “difficult” ones, are more narrow and demanding in their husbandry requirements, needing a particular water chemistry, for instance (e.g., soft and acid water), or a diet rich in live, rather than prepared, foods. And those deemed “unspawnable” are simply species whose captive spawning has, as yet, resisted the usual formulaic cichlid approach; these are species awaiting experimentation and discovery. For many cichlid hobbyists, the appeal of these unspawnable fish is simply the challenge of being the first to elicit and record a successful instance of aquarium breeding resulting in captive-reared young and adults.
For these fish, we must determine what the missing ingredient or the missing catalyst is. What do they need? And what aren’t they getting? To answer that question we must be ready to learn all we can about our target fish, where it comes from and how it lives, and then apply that knowledge. And we must apply that knowledge experimentally, persistently and patiently. As I explained last month, I call it the “DOPE” principal—to succeed with unspawnable fish, one must be Determined, Obsessive, Persistent (and patient), and Experimental. You must be willing to think outside of the glass box, and you must be willing to try new approaches methodically and persistently until the particular species yields its secrets.
My friend Lee Newman, Curator of Tropical Waters at the Vancouver Aquarium (and whom I profiled at some length in the last column), is one of these types of “DOPE”-y aquarists. I will use two recent examples of his successes spawning the unspawnable to illustrate what I mean—this month, his successful approach to spawning the sharp-headed demonfish Satanoperca acuticeps, and next time, the mythical goby eartheater from the Xingu rapids, Retroculus xinguensis. Two jobs very well done, as you will see.
Having become enamored and obsessed with demonfish, eartheaters of the genus Satanoperca, Lee undertook to acquire and captive-spawn as many of them as possible. Kullander (1986) resurrected the genus Satanoperca Guenther 1862 (“Satan’s perch”) to hold those eartheaters of the “jurupari” group, which had been lumped with species like surinamensis, brasiliensis, steindachneri, etc. in the genus Geophagus Heckel 1840 by Gosse (1976) and others before him. (Kullander also restricted the genus Geophagus to the “surinamensis”types, leaving the brasiliensis group and the “red-hump” steindachneri group even today without formal genus names.)
The genus Satanoperca as currently understood may be split into two groups—the unspotted demonfish: jurupari, leucosticta,(possibly) mapiritensis, pappaterra, and many other geographical variants that may well be described as distinct species in the future, and the spotted demonfish: acuticeps, daemon, and lilith. The unspotted demonfish, though not easy, have been spawned successfully in captivity with some effort by a long list of cichlidophiles. These are either immediate (ovophile) or delayed (larvophile) mouthbrooders, either picking up their newly laid eggs or their hatching, yolk-sac fry respectively, and sheltering them in their buccal cavity until free-swimming and beyond. Lee has contributed to the roster of unspotted demonfish that have been spawned in captivity and had their reproductive behavior noted.
The spotted demonfish are another matter. Whereas S. daemon has been spawned rarely and relatively recently (e.g., the American aquarists Tom Wojtech and Martha Clark independently in the mid-1990s in this country) and has proven to be a non-mouthbrooding pit spawner, up until Lee’s success in 2001 S. acuticeps had proven unspawnable, despite having been known to the aquarium hobby since the early 1900s. (S. lilith was only recently described in 1988 by Kullander and Ferreira and has been only sporadically available in the hobby on either side of the Atlantic—it has not yet been captive-spawned.) Lee’s success with S. acuticeps was due in large part to both serendipity (as many discoveries are) and, more importantly, to his own observational skills and willingness to think creatively and experiment.
As these stories often begin, a trio of sub-adult S. acuticeps was gifted to Lee by an eartheater friend of ours, Frank Choy, during another of Lee’s heroic roadtrips to attend a fish society meeting, this time down in San Francisco. Having been so generously given this trio, Lee then spent the better part of the weekend driving around to fish stores in the Bay Area trying to find some more. He found four, and together these fish would become the nucleus for a “breeding colony,” or so Lee hoped. When he got back to Vancouver, he put them together in a 90-gallon tank for their initial quarantine and grow-out.
Having seen how they live in the wild, and having at hand accounts of the habitat by Kullander and Ferreira (1988) in their description of S. lilith, which occurs sympatrically with S. acuticeps over part of its range, Lee knew that they are found in slow-flowing rivers, generally over a mixture of sand, clay, and mud substrates. There are usually waterlogged branches and logs on the bottom, as well as some flooded terrestrial grasses and shrubs during the high-water season. With these conditions in mind, he set up the tank with a fine sand substrate about 2 cm (just less than one inch) deep, with several pieces of waterlogged wood offered for cover. The tank water was aged, unaltered tap water (pre-filtered over a copper-removing resin), and filtered with large air-driven box filters packed with a small amount of crushed coral to maintain pH, and floss/foam layers for mechanical and bacteriological filtration. The water temperature was maintained at 82° to 84°F and the pH was buffered to between 6.7 and 7.0. Water changes were large and frequent, about 75 to 80 percent every two weeks, resulting in a low nitrate level of 5 to 10 ppm (transcribed from Newman, 2001. Buntbarsche Bulletin 207:1-11). So far, just excellent fish husbandry. What else would you expect from the Curator of Tropical Waters for the Vancouver Aquarium?
Now the serendipitous part and the apparent (and surprising) key to their captive spawning: diet. Although usually offering frozen bloodworms (chironomid larvae) to new cichlids, this time Lee gave the newly situated S. acuticeps frozen Daphnia—simply a convenience, since he was feeding other tanks with it at the time. As the frozen Daphnia slowly sank, the fish approached and began pump-straining them from the water column like a filter-feeding basketmouth (e.g., Chaetobranchopsis sp.). Also, they retrieved the missed Daphnia that had sunk to the sand surface by picking at it, not sifting the substratum as one might expect from a Satanoperca species, for instance S. jurupari.
Something was wrong here—or was it? The fish were not following the formulaic eartheater playbook. Consulting the Kullander and Ferreira (1988) paper again, Lee discovered that gut analysis of S. lilith showed that they were feeding on cladocerans (“water fleas” like Daphnia), conchostracans (“clam shrimps”), and ostracods (“seed shrimps”), in addition to insect larvae and plant debris. All of these crustacean groups are generally small foods under a half-inch in length. Although no gut analysis was done on S. acuticeps, the authors in this same paper discussed differences in the mouth shape and jaw dentition of S. acuticeps relative to S. jurupari that suggested to them that they might take pelagic (swimming) food rather than sifting for it. As Lee (2001) put it, “Apparently I had coincidentally fed them just the right food!” Indeed.
The rest of the exercise was simply the result of this serendipitous, but important, observation. In addition to providing frozen bloodworms and spirulina flakes, Lee fed the S. acuticeps a homemade gel food to provide the missing crustaceans and plant debris. It was made up of equal parts of frozen green peas and frozen krill with added spirulina powder and crushed cichlid pellets, ground fine in a blender and bound by gelatin (modified from a recipe in Enjoying Cichlids [Cichlid Press]). When placed in water, the gel food was easily broken into small particles by the fish, which they did. He also fed live cultured (when available) and frozen Daphnia.
He moved the seven S. acuticeps to a 180-gallon tank set up similarly to the 90, but with much larger homemade box filters sized to the new tank. He also added three subadult altum angelfish Pterophyllum altum as dithers. By February 2001, six months since their acquisition, the four larger fish (males, average TL about 6 inches) and the three smaller fish (females, average TL about 4¼ inches, with distended bellies) began courting.
The first spawning occurred in April. They dug a large pit in the sand, down to the glass, and pasted their 150 to 200 eggs to the bottom, then lightly covered them with sand. Unlike the mouthbrooding “jurupari” types, S. acuticeps (like S. daemon, and probably, though we don’t know for sure, S. lilith) are pit-spawning substrate brooders. The rest of the captive spawning—from newly-hatched wriggler to free-swimming, feeding fry—was relatively normal and uneventful, though the parents were not very proficient at guarding their free-swimming fry. The adults dug the pit to a size of 60 cm (about 24 inches) diameter, which covered fully one-third of the bottom of the tank! Lee had several successful subsequent spawnings from various pair combinations and was able to raise the free-swimming fry to distributable size by siphoning them off and rearing them away from their parents. When left with the parents, they were typically eaten by marauding tankmates under these conditions.
What did he do differently? Remember, he had kept and spawned several species and geographic variants of non-spotted “jurupari” demonfish before. What was the key that unlocked the captive spawning of S. acuticeps, the first recorded instance in the international cichlid literature (see Weidner, 2000. South American Eartheaters [Cichlid Press])? The observation that they “did it differently” from other demonfish, that they filtered rather than sifted, and tailoring their diet accordingly. This is what made it possible. Not that his normal cichlid diet was somehow nutritionally deficient, but who would think to feed such small food (Daphnia) to such relatively large fish? Who expected them to be pump-strainers and pickers rather than normal sifters? Also, he provided general tank husbandry conditions that matched what they experienced in the wild. Research, openness, innovation, experimentation, and the courage to think outside of the glass box. A big “atta boy!” and kudos to Lee for this singular accomplishment!
Next time, another notch in the “impossible” belt: how Lee successfully spawned Retroculus xinguensis for the first time in recorded aquarium history, achieved again by thinking outside of the glass box—a habit all good aquarists need to cultivate.