CichlidFish.com - Fish That Think.

Hi, Nytemare, and welcome!  There are a few small cichlids that you could keep in a 5 gallon tank, but Red Devils are not one of those.  They become quite large.  Even a convict would be too big for a 5-gallon. 

you would need at least a 29 gallon tank with a strong power filter for a convict.

I have keep a pair of cons in a 20 with no problem just lots of filter power, and regular water changes but I'm unsure about any thing except maybe a dwarf of some kind that you could keep in a 5 gallon, and even then you could probably only get one.  Try dwarf rams don't know if you could get away with one or not but they look beautiful if you can. Or maybe a small African shell dweller of some kind, their are a few that stay small.

5 gallons is really too small for a pair of anything if you think about it. You would have to house the parents, as well as the babies they produce. It's really hard to clean a tank with babies, so that tank would get dirty way too fast. I don't think the pair would be too happy that crowded. Maybe they wouldn't have spawn at all in something that size, especially if they are unhappy.

You can get 10-20 and even 30 gallon tanks for really cheap sometimes. I would go with one of them. That way your fish won't be crowded and unhappy and it will be much easier on you as well.