they get to about 7 - 9" max in the home aquarium. so even a tank as small as a 20 long would be a suitable home. feed them earthworms and maybe blood worms from time to time. they are pretty easy to keep. the only really important things to tell you are: 1. make sure there are no holes that the eel can escape out through in th lid. they are escape artists. i have heard way to many people talk about how they got an eel and then a few days later it died because it had jumped out. 2. they need a fine substrate, in other words, something like sand. but from the pic it looks like youve already got that. and make sure they cant get into your filter. they can be kept with others of their own kind so long as they are all peacock eels and not simply spiny eels.if you get a second one, keep him isolated in a quarantine tank for at least a month to ensure that it does not have any bacterial or parasitic illnesses that could be spread. i have lost peacock eels because i did not quarantine. it hurts to lose a beloved pet so be careful ok.