I just bought a 15 gallon tank. 1. About how many fish can i fit in there?? What is the size limitation? 2. Also, without thinking, i bought live plants for my tank called kyoto grass plants (Ophiopogon japonica) without checking their light needs. i have a single 25 watt flourescent bulb in my tank, will that be enough light? also, what is needed to keep live plants healthy (do u need fertalizers or anything like that?). thanks for the help!!