Apistogramma agassizi, Agassiz's Apisto

Apistogramma agassizi[i]. The original Apisto, the first one that was on the U.S. market, now comes in several snazzy "selected" versions, of which I've kept the "Red Agassizi," which first appeared on the US market in 1988. This species has the widest distribution of any Apisto, in small streams and seasonally flooded grassy bottomlands of the Amazon River basin, along the upper Amazon-Solimões into Peru and downstream through Brazil to the Capim River basin; as a result, color variants have arisen naturally in isolated populations. Though many of these variations will naturally occur among batches of tank-bred fry, it's interesting that wild females, when they are experimentally given the choice, will choose the male closest to their own regional morph, which supports suggestions that speciation is partly driven by females' sexual choices.
 
Though 5- and 10-gallon tanks are often recommended for breeding Apistos, you may be creating unnecessary difficulties if you're giving your breeders less space than 15 gallons, or if your planting isn't dense enough, or if you aren't offering enough alternative cavelike spaces with narrow openings. The narrowness of the opening has security value for the breeding pair. Alternately, some Apistogamma species spawn in annually flooded  bottomland meadows in as little as 2" of water, where larger fish can't penetrate: so, dropping the water level may give your own Apistos confidence. Though some gentle target fish can help reinforce the pair-bond, bottom-dwelling catfish can be disruptive or worse. Otocinclus may be better tankmates than even the mildest Corydoras. A little nightlight in the fishroom may be reassuring to a female guarding her wrigglers. Or it may give her just enough light to eat them by!
 
Rather than the ideal conditions of endless summery heat and the softest possible peaty water and pH below 6.0, a change in water conditions may provide the better spawning cue. Try letting the carbonate buffering build up, perhaps with some crushed coral in the filtration, over a period of weeks, then do a 75% water change using r/o water spiked with some peatwater.
 
 
Links.  Some Apistophile postings about A. agassizi, including Oleg Kiselev's advice about breeding these touchy Apistos, are archived at The Krib. The range of wild-type A. agassizi is illustrated among the Apistogramma featured in Martin Rosjorde and Tom Christoffersen's ApistoSites, under A-numbers A-234-243. Some posts about the "Rio Tefé" population of this wide-ranging species are also archived at the Krib. There is a good summary of A. agassizi at SeriouslyFish. 
 
Apistogramma agassizii at FishBase. Apistogramma agassizii at Wikipedia.