HI have just got my tank cycled fishless. have added my first 4 fish had in mind rasbora but when I went to lfs had a look around and saw Odessa barbs asked how big they will get was told 2inch max so thought ok liked the look of them now got them in the tank as of last night but have read up on them and some say 2inch others are saying can get as big as 4 inch they aren't even in a full school at the min and looks like I could already be at the limit of fish I can have my tank is 27 gal.what can I do? Take them back before they grow? Also are very inactive at the min just hiding at back of tank is this normal? Am fairly new to the hobby have had a 10 gal a couple of years ago wanted to do everything right this time!