well my tank was cycling nicely along fishless. looking lovely. but since then i have had to be the knight in shining armour i have taken in four (what i believe to be gold or rosy) barbs. while some dear friends of mine move house and go on holiday. i have given them spectrum pellets those little 1mm brown ones. i think they might be too big to fit in thier mouths they kinda suck them in and spit them out. i have to crush them to a almost powder. is this a problem

?
pH 7.6
ammonia .25 nitrItes ZERO!!! nitrAtes 5-10
so now i have these fish the food has started to stain my blue gravel. i put 8 of these 1mm square pellets in twice a day so 16 in total. will a vaccuum sort this out

just the food they dont eat sits on the gravel and goes a funny colour. there are only 4 little fish just over an inch each
in a nut shell
do i start to do regular water changes now?
do i also start vaccuuming portions of my tank?
should i try fish flakes? and feed a little less often
they are having a blast in a massive tank all to themselves. and as to be expected i getting quite attatched
thanks as always for your help fishloreans
Dazzler