There is no organism in which enclosure size limits growth. A small enclosure gets filthy faster, it is the filth that will harm the animal.
I once raised a goldfish in a 1 gallon container. In six months it was approaching 12" long. and was in fact so long it could not turn around in it's enclosure. Clearly in this case cage size was not a limiting factor.
The enclosure was a hard plastic mesh submerged in a 60 gallon tank of fresh clean well filtered water. I fed three or more times a day and the temp was mid-70's.
Had this same experiment been carried out in a one gallon jar the results would have been very different. The filthy water would have harmed the kidneys of the fish allowing for disease and likely death to occur.


