I have a 10 gallon and have grown such a love for my guys, there are three in there. (They are all small, 2 use 1/2" shells and 1 uses 3/4". I am thinking of maybe getting 1 more - not right away, but in a couple months maybe, (I will probably have a new tank by then, but JIC I don't) would it be too much to put one more that size in there to bring the total to 4 small? Just wondering when is too many based on tanks? Thanks in advance.