I have keeps them for a while now. I usually keep it one to a tank. Becareful they love to explore and will climb up your filter pipes and on to the lid if your aquarium. I had one that would walk around on top then jump back into the water when some one walks past. They can be keep with just about anything that isn't naturally aggressive. I have tiger barbs glass cats and a ghost knife with mine. I've had them live over two years or as short as 6 months. Kinda depends what condition they are in when you buy them.