I just got one and I love it. It is about 1.5" long. How long does it take them to grow to adult size? Could I have two in my tank? I have a 29 gallon tank.
Growth rate is variable, depends on temp, diet, etc., but a 1.5" juvie will likely double in size in a few months. I wouldn't recommend 2 adults in a 29 unless it's an established pair. If they're both adult males there will be conflict over territory. Also, a single adult is quite capable of keeping a 55 spotlessly free of algae. Having 2 in a smaller tank simply means there's less grazing available, and they'll need to be fed veggies more often.