The way to sex Hoplosternum thoracatum is to look at the first hard ray of the pectoral fin. The male will have longer more pointed pectoral fins and the first ray will be thicker and have a reddish-orange tint. The females pectorals are short and rounded. I had two males and one female. I set the female up with one of the males in April of 1995 in a 15-gallon long tank with a sponge filter. The water was from the tap and the pH was 7.5 and the hardness was 80 ppm’s. I fed the pair live tubifex worms and frozen blood worms. Notice the long barbels of this species. This species find their food by odor. Dropping a clump of tubifex worms in the tank can be spooky to the fish if the worms touch their body. Once the worms are on the bottom of the tank and the fish get the ‘odor’ of the food, they go right for it.