right now i have 1 in a 10 gallon.... and 2 in another 10 gallon... they werent getting along so everyone has been moved around... i also put 1 convict in with my pair of kribs... hes small and doesnt bother the kribs and the kribs dont bother him so its working out well now.... i have one big mean convict in 1 of the 10s.. he hates everyone so he can stay in that tank by himself... then i have another pair in a diff 10 ... theyre both small aswell.. about an inch