Paracheirodon axelrodi: To breed the cardinal tetra we first clean the aquariums well and fill with appropriate water less then 3 DH, Melbourne water is ideal I filter it 2 to 3 days over peat The best temperature is 23� to 24� C, instead Plants i use nylon mops! disinfecting is more simple. We do not use sand! With "soft water fish" it is substantial not to hold the animals outside the breeding period in to hard water, smaller deviations however is without meaning. The breeding aquariums are to be set up in such a way that only absorbed light falls in the tank. for breeding, cardinal tetra prefer dawning light, the eggs are photosensitive. Only if the brood swims free, we light up normally. If The fish are ready there will breed within three days. If the fish did not breed within the sixth day, we remove the breeders from the breeding aquarium. We may not feed the fish in the breeding aquarium because of pollution. These fish pursue their eggs only rarely during breeding. If necessary, one puts nylon mops on the bottom of tank and weights these or uses a screen netting about 3 mm which can be wedged across the bottom of tank. the young fish swim free on the fifth or sixth day and we begin to feed, the free swimming fry it is difficult to observe, since the young fish are in the darkest places of the tank closely over the bottom. Since they are glasslike transparent in addition, one sees actually only the eyes, a good magnifying glass to check is important. For the first days of life we feed cleaned Paramecium and fresh hatchet brine shrimp. The further rising of the brood takes place with good dry and living food. Their raising is not hart, if we feed twice daily small quantities of food. With sex ripe young cardinal tetra I usually get the best results, it is to no purpose to set up older fish for breeding. I do feed the fish who I going to breed with, grindal or small enchytraen; the PH is of no influence on the development of the eggs, as long the value is between six and seven.