well he was in a 30 gal with three bettas a placatomus and catfish...he then killed a betta and the placatomus and i moved him to a 1 gallon where i took the pics... now he is in... i wanna say a five gallon...but i aint quite sure... here are some pics....
You should rehome the fish if you cannot find a decent sized tank to house it in, a fish that big (assuming it is either a koi or a goldfish) should be in at least a 50gal tank at its current size. Although i don't like talking to much on the subject of cruelty, keeping the fish in a tank that small is basically cruel when it comes down to it (whether you know this is cruel or not, this is the case as it currently stands).
Tropical fish should not be mixed with coldwater fish or vice versa, some goldfish and koi types are sub-tropical at best but none are tropical fish- keeping any fish in the wrong temps will mess up its metabolism, weakening it, and inevitably shorten its life span- there are many ways a fish can die due to wrong temps. Keeping a fish in a tank too small will also have similar consequences- the fish will weaken and become very stressed, making it vunerable to desease, and its growth will be stunted and its life expectancy will be dramatically shortened.
So if you want to do your best for this fish and look after it responsability, either buy a proper sized tank for it right now, or rehome it to someone who can look after it properly.
Its not the fishes fault it killed the other fish- goldfish and koi are well known for killing or eating fish which are small enough to fit into their mouths or slow/vunerable enough not to defend themselves against attack. The moral of this story? Research your fish thoroughly and properly before you get them and tell your relatives and friends not to buy you animals as presents unexpectedly.
Right now you need to take an imediate course of action to prevent any further suffering to your pet fish, but we will need more info on your situation to help you. How many fish and what types do you have in each tank you own plus each tanks dimensions (width, height, length)? Do any of the tanks have filtration (and if so, what type) and heating? How often do you clean your tanks on average and how do you go about it? The info you give us (which is very important) will give us a clearer pciture of your situation and more info to work on so we can give you the best and most accurate advice.
With the sizing of the pics, use the program Paint (found on most computers now days) and go to Image and re-size the pic there.