It is an interesting hypothesis. I think I do need a bigger tank........Csababá;4847626; said:You should get a bigger tank!
(sorry, I could leave it)
Is it possible that they get more food and grow larger in a smaller tank without threat?
Actually I feel there are several reasons.
Not all fish grow anywhere near their maximum size for their species. I did not grow anywhere near the max for my species which is 8' 11 1/2".
The 2 fish I have were raised in small tanks and then traded in to pet stores. The pet stores had no idea of their age so it is conceivable they were as large as they could get in the unknown size of the tanks they were in and then grew a few more inches in my tanks.
Since I was able to get them to eat pellets and flakes, food is not a problem as they also eat smelt, mackerel, herring, trout and salmon and as I mentioned they hunt and catch african cichlids.
Also their size could be related to their parents size.
In a study I read on the web of Morulius chrysophekadion
The maximum size of the same species of fish varied depending on the country they lived in. The difference was very large and was surprising to the
to the researchers.
" Morulius chrysophekadion is one of the large cyprinids. The survey confirmed its distribution throughout the basin, from the northernmost stations in the Lao PDR and Thailand to the southernmost stations in Bassac and the Mekong delta in Viet Nam.
There is some variation in the maximum size attained by this fish in the four countries. In Viet Nam, maximum reported size of Morulius chrysophekadion was 40 cm, while in Cambodia and the Lao PDR it was 70 cm. In Thailand, fishes of 90 cm were reported (about 7 kg), which is considerably higher than the maximum size of 60 cm, reported by Rainboth (1996)."
Since the Notopterus chitala also lives in these areas it is conceivable that size could be related to the area they come from.
A pic of my 26" Morulius chrysophekadion I bought in 1992 at Marine Resources (Sean Wilson) in Brampton at 1 3/4" for $1.75. He is still alive and spend winters in tanks from 225 to 520 gallons and summers in ponds 16/18' by 8'.