yes, the hex has a ugf and so does one of the ten gallon tanks, I already took the ugf out of the other ten gallon and as soon as I clean the again I am taking the other one out to and just run off of the hob filters. (ugf=to many problems) You probably shouldn't keep 6 fish in a 2.5 gallon but they are small fish and it's just temporary and it has a good filter. thanks for the reply Scarab.