These barbs originate from Sumatra...they can reach a lenght of 2.5 - 3". They should be kept in groups of atleast 6 and like to have alot of swimming space. To answer your question of how long before they reach full size,i think it all depends...If they are kept in in-adequate conditions then they will never reach their full potential....What size tank do you have them in? For a group of 6 or more i wouldn't recommend anything smaller than a 30 gal IMO.
hope i helped.
i have 12 in a 75 gallon tank. along with 6 b.rams, 3 p.tetras, 1 parrot fish, 1 ciclid (cant remember its name) 1 clown pleco, 1 common pleco and i think thats it.
hi
we have now 8 tiger barbs we started off with 6, 16 months ago teeny little guys & theyve grown to just over 2.5 inches in that time, we sadly lost one to dropsy recently but the others are going strong & from my observations it was about a year till they got to this size(2.5 inches) we recently got a couple of new tigers & theyre still quite small in comparison to our originals(about an inch big) makes us laugh watching the new upstarts trying to give the old boys a run for their money (in the tuffness stakes that is) in fact its almost like the older boys are saying yeah yeah you can act tough but we cant be bothered anymore & dont care......sod off & leave us in peace