I'd say no, it wouldnt have any effect on the growth rate, alot of snakes prefer small spaces, but keeping a large snake in cramped conditions, im sure could have negative effects on its health,
The thing with fish is a bit different to reptiles, saying fish only grow acording to the size of their enclosure is true to a certain extent, when fish produce waste, they also emit a chemical with it, if this chemical builds up to high levels it will stunt the growth of the fish. This would only usually happen in ponds and small lakes or any small body of water, i.e your aquarium.
They only way you could immitate this is by not doing any water changes to your aquarium, but there are other chemicals that can also slowly build up in aquarium enviroments and when they reach toxic levels they can kill everything in the tank, so regular partial water changes are recomended as essential and id say a necessity, otherwise you wouldnt be keeping the fish in the best conditions you could provide.
Im sure no one on here only replies to a thread with the sole intentional view of proving you wrong, although some may be slightly intimidating than others in thier replies. :wink: