3 gallon planted tank

Just a quick question, I have 3 white mickey mouse platies in my 3 gallon (heavily planted) tank. Is this ok? I got them today, they seem to have settled in well. There's a good variety of algae in there that they've already taken to munching on. They'll be ok just as long as I keep the water...

I have a 3 gallon planted tank that used to have a betta, nerite snail, and otocinclus. the nerite snail died awhile ago, and my halfmoon betta died on sunday at 3 years old... now it's just the lone oto. (I know, I shouldn't have a lone oto in such a small tank, but he's been fine for the past...