Q. I have three cichlid fish in a 40-gallon freshwater fish aquarium (two Jack Dempseys and one firemouth). Recently, I noticed that there are less than 100 baby fish in my aquarium. I took the firemouth out of the aquarium and put it in a smaller space temporarily. It doesn’t look like the Dempseys are eating the babies, but I’m not certain. One Dempsey is on the small side and looking very beat up, and its color has changed dramatically. It looks black, and you can hardly see its stripes or spots. One pet store employee said the fish is probably depressed, but I’m not really sure. What should I do to save my three fish? How should I deal with the babies?
A. Congratulations on becoming a fish parent. It’s a common surprise to find a swarm of baby cichlid fish in an aquarium — though one usually spots the eggs first when they notice the parents keeping tankmates at bay.
Your baby Jack Dempseys are easy to raise, but if you want to maximize the number that survive, move them to a separate aquarium for growing out (or remove the other fish). Jack Dempsey parents are protective of their young and may indeed guard them until they grow to around three-quarters of an inch. But this is rare in the aquarium. Tankmates tend to eat the young, and the parents may even do so themselves. It’s easy to keep predators away in the wild open spaces of nature but not in the confines of an aquarium.
The smaller Dempsey is usually the female. Darker colors can show breeding condition. Darker colors can also show stress. Since she’s beaten up, I’d bet it’s the latter. Male cichlid fish often become aggressively protective of the young — sometimes to the point where they beat up the female. So, if you don’t remove the young, you may need to remove the female, or isolate her with an aquarium divider or net breeder basket. Happy fishkeeping!