Apistogramma cacatuoides, the Cockatoo Apisto

Apistogramma cacatuoides ("Cockatoo Apisto"). This tongue-twister name is "KACK-uh-two-OI-dees," as colorful "as a cockatoo" because of the male's crested forelock of a few extra long dorsal fin spines. As females mature, they develop a modest version of the crest.
 
There are currently 52 scientifically-described species of Apistogramma, plus about another 90 in hobby-oriented literature, according to guru Mike Wise. With so many species, and so many distinct populations that might turn out to be legitimate species, since 2005 some German aquarists have begun assigning new imports "A-numbers", taking a tip from the useful unscientific "L-numbers" by which Loricariid catfish are known, while the backlog of scientific descriptions accumulates.
 
Now there are maybe a dozen Apistos that might turn up at a big LFS, though not all at one time. Apparently we're catching this genus right in the process of speciating. There are thirteen species-groups with closely-shared characteristics, one of which is the A. cacatuoides species complex, which includes A. luelingi and A. juruensis, neither of which is likely to turn up frequently at your LFS. This group is characterized by robust but slightly elongate bodies, the large fleshy lips of mature males (my cockatoos have sky-blue lips) and their variable flank streaks, the extended anterior dorsal fin spines I mentioned, and caudal fins that are produced at top and bottom into points, in a shape termed "lyrate." The males are polygamous harem-keepers. Sometimes females in yellow-and-black brooding dress blur their lateral band and develop a side spot, which comes and goes. Apistogramma cacatuoides has many varying color morphs, which have been stabilized by selective breeding. My original patriarchal male was a "Triple Red," so-called because the red and black markings of his dorsal and caudal fins extend to his anal fin. As he matured his blue lips became fleshier. His bulldog lower jaw was white, with blue suborbital streaks and a blue chinstrap. His sons carried on his features. Randy Carey thinks we've all gone overboard in admiring this domesticated "Triple Red" feature, to the exclusion of the subtlety of wild types. The Apistogramma pros rate A. cacatuoidesas one of the good "starter" Apistos, because of its tolerance for pH ranges even slightly above pH 7.0, because of the docility of the males with one another and the general readiness of these fishes to breed. Other "starter" Apistos often mentioned, you'll be interested to know, are A. steindachneri, A. macmasteri, and A. "Schwartzsaum."
 
The type locality quoted when A. cacatuoides was first scientifically described in 1951 was given as near Paramaibo in Suriname, which in reality was nothing more than a trans-shipping point. The original collector was described as a sailor. At the time the genuine habitat must have been considered a "trade secret," for this widely-distributed species naturally occurs in clearwater or whitewater small tributary streams of the upper Amazon in the neighborhood of Iquitos and of the Rio Ucayali in eastern Peru and Rio Jurua in westernmost Brazil, all on the upper edges of the Amazon basin. David Soares says that Uwe Romer found A. cacatuoides in incredible densities of up to 100 in nine square meters, in leaf litter as much as a meter thick. Soares has kept up to 135 A. juruensis in a 20gal. tank, 700 A. cacatuoides in a 150gal. tank. Truly, cichlids for apartments, eh!
 
Apistos do like some tropical warmth. Temperatures below 78°F will depress them and blunt their appetites. But you can keep them for weeks in summer at 86°F. The wide natural distribution of Apistogamma species in small watercourses, has encouraged speciation. The native watercourses are isolated from one another by impassably large rivers, which encourages variation in small populations that don't have a chance to interbreed. When James Russel Wallace was exploring the Amazon in the 1840s, he was impressed with the broad rivers that isolated animal populations and encouraged the variation that led to new species. In Discover Magazine, April 1997, Virginia Morrell reported "On the Origin of (Amazonian) Species." She outlined work that Jim Patton of Berkeley is doing on Amazonian mammal distributions. The distribution of Amazonian mammals is surprisingly discontinuous, a pattern which reflects ancient ridges and shifting river patterns. Her article has interesting ramifications for freshwater fish species too, because these shifting discontinuities have sparked the amazing species radiation of Apistogramma and some Loricariid catfishes.  
 
I was reading recently about a genetic "failing," in which, as a male Apistogramma ages, his snout widens and curves into a "bulldog" nose that reminds you of the front of a VW bug. Other Cichlids develop a nuchal hump without being considered disfigured, and I think that, rather than a failing, this is a normal development, which only comes with full maturity, after a year or more. I've read that this "VW nose" isn't ever seen in the wild, but then all the Apistogramma males seen in the wild are never more than three-quarters grown. They just don't survive to the age they reach in our aquaria. In nature, males are more expendable than females anyway: the "harem" style of breeding insures that fewer males are needed to carry on the species. Females lurk safely in rolled-up leaves or husks or under roots, but the larger, gaudy territory-patrolling males are more vulnerable to predators. At any rate, I may be biased, for my "Cockatoo" males develop this feature in middle age. I have seen the "bulldog nose" noted for various other Apistogramma species, though not for cacatuoides. Apparently the genes for this feature are widespread through the genus. And that suggests that the mutation lies deep in time. When I first posted these reservations, at AquariaCentral, Marcus posted, February 29, 2000, "Actually, every older cacatuoides I have ever seen exhibits this "bulldog" look. I assumed it was just part af the maturation process. I wasn't aware that it was a defect. You are correct in saying that a long-lived fish in the wild is a rare occurrence." My original female was at first a little on the small side. She was only half her male's length when they began spawning. Expect your young males to begin spawning at 4 to 5 months, before they're quite an inch and a half long, and when the female is just an inch overall! Apistogrammas will train you to feed them nothing but live food, by ignoring flakes unless they are seriously hungry. Wayne Liebel noted in an unsurpassed April 1994 Aquarium Fish article on keeping Apistos, "The most successful apistophile I ever met fed his fish live foods and changed at least ten percent of the water in his tank, every day! This was, perhaps, excessive, but the fish were gorgeous and he bred everything." Worms and sinking bloodworms are preferred; Apistos are reluctant even to go to the surface after mosquito larvae and fruit flies. Oleg Kiselev remarked in 1992. "...in the wild they spawn in huge leaves curled into tight tubes or in tennis-ball-sized nutshells... these fish like a lot of cover." So I give them roots and tennis-ball-sized coconut shells, and overhead cover with duckweed, water sprite and Pistia. The hanging "roots" of floating plants act like Java Moss to encourage a well-developed biofilm that supplements any food you can offer the fry. Microworms and newly-hatched brine shrimp nauplii are good early fry foods. Apisto fry are almost invisible. They're a translucent golden tan with minute dark flecks, the scale and color of a grain of coarse silica sand. They hang motionless. Only when they dart are they visible, and in the cluster of fry, they seem to move individually only when all their closest neighbors are freezing. It's not a good idea to mix various Apistogrammas species in the same tank. The females of the A. cacatuoides group are especially easy to confound. A. cacatuoides stand out from most Apistos by having three rather than four infraorbital pores. But details like this will not discourage Apistogramma species from interbreeding in the artificial confines of our aquaria.
 
Harem breeding. If they're given the chance, A. cacatuoides will form a harem, where one male patrols a territory that has been sub-divided by a group of females, and he spawns with each of them in turn. I kept my first successfully-breeding cacatuoides pair in a 10 gallon tank, all by themselves, after a former male half-swallowed an Otocinclus in a fit of territorial defense, and both of them died in the event. I offered the pair many caves formed from small slabs of sandstone laid one on another at a slant and then mostly buried in fine gravel and coarse sand. More dark hideouts were provided by coconut shells. Currently, in another 10-gal. tank with leaf litter and many hideouts, a single male was successfully  tending a harem of four sisters, who had never been separated. In these crowded conditions, however, I didn't get to raise young. A harem forms because the females cannot leave their eggs. I have thoughtlessly picked up a coconut shell that contained a clutch of eggs I was unaware of, and the female has risen up, following her clutch pasted to the domed interior. Once I drew out an occupied coconut shell with the courageous mother remaining inside even as the water drained away. With the females dividing up the habitat into minute broodcare territories covering a few square inches, and immobilized there, it falls to the male to control as large a section of these nesting crevices and miniature caves and rolled leaves as he is able. That's why Apisto males have been naturally selected for larger size. Where the male shares in parental responsibility, a pair bond must be formed. But harem females regularly exclude the male from brood care. With some A. cacatuoidespairs, the male will try to help herding the fry. With others, his "help" consists of sucking down the young. I noticed an inexperienced young A. cacatuoides male pick up fry in his mouth and transfer them, as his female was doing. She was on him in a flash, charging him furiously, backing him away from the brood and forcing him away to the edges of the territory by angry tailbeats. It seems as though female-only brood care is a recently-evolved genetic pattern with this species, one that's still not firmly fixed. Females in brilliant black and yellow breeding dress get a lot more respect from other females in my dense 10 gallon colony. A brooding mother enlarges her territory at the expense of her neighbors, and her neighbors tend to allow her more "elbow room." I'm sorry to relate that there is a lot of competitive fry-eating in my dense colony. Though the four females are sisters that have never been separated- and each share half their DNA, there is still some "DNA-jealousy." If there were some cooperation among the sisters, fry would survive.
 
Unbalanced sex ratios. Many people have noticed wide-ranging unbalanced sex ratios from spawnings, where almost all the fry will turn out to be male or female. Conflicting reports as to how pH and temperature affects these sex ratios have been settled recently. When Uwe Römer and W. Beisenhertz investigated connections between pH and sex ratios in 33 species of Apistos and two other South American dwarf cichlids, they found that, in general, the higher the pH, the greater the proportion of females in a brood, and the higher the temperature, the greater ratio of males. The most sensitive period in skewing the gender ratios was about 30 to 40 days after hatching. George Barlow reported this in The Cichlid Fishes, 2000, p. 57.
 
Links. Apistogramma cacatuoides at FishBase. Very informative A. cacatuoides posts from the Apistogramma mailing-list are archived at The Krib. A. cacatuoides from Rio Nanay appears among the Apistos in Martin Rosjorde and Tom Christoffersen's extraordinarily fine ApistoSite. Kaycy Ruffer's experiences breeding A. cacatuoides are at Cichlid Forum.