high my name is ryan im from peterborough ontario canada . i bought a 30 gallon tropical fresh water aquarium and too start i have one fake plant bautful blue gravol and it sits on top of my dresser in my room. the community is a semi aggressive community fish tank. i got 2 rainbow sharks 1 angel fish 1 moonlight orgami and a pleq algae eater. my question is how big do they get how often should i scrub the tank replace water etc and do i have too stick with semi aggressive or can i put a community fish as long as its not too small etc. and this is how i introduce the fish into my tank i put the fish in my tank in the bag leave them there for 30 minutes then i fill a big bowl with half my water in the tank and half the stores water from the bag then i transfer them one at a time into the bowl then grab my net and take them out of the bowl into my tank using the hand net one at a time. i found it good because then i dont get the stores water in my tank and i just dump the bowl down the sink good method i find it the best. i can prob only fit 3 more anymore will make it hard too clean or im lazy lol. anyway its long at 30 gallans not a box tank. i think ive done everything well so far i just need to get a log so the rainbow sharks can hide somwhere other then behind my filter lol. any advice corrections info 30 gallon tank rule of thumbs would be greatley appreciated im a beginner thankyou.