My nephew has a 5 gallon mini-bow tank that has cycled and he has one albino cory catfish in it. He would like to add 1 Male Lyretail Guppy, 1 Male Orange Sunshine Guppy, 1 male Green Cobra Guppy, 1 Male Blue Cobra Guppy. Any problems there? Please don't tell me how corys like groups either, I know this, however, in tanks less than 20 gallons they don't shoal up anyways so less than 3 can be gotten away with.