1. Goldfish belong in bowls:
There is not one species of goldfish that would actully fit in a bowl, or any tank under 30 gallons. The general rule for goldfish (depending on species) is 30 gallons for the first fish, then an additional 10 gallons for each fish after.
2. Goldfish are a great beginner fish:
Wrong again. Goldfish are one of the dirtiest fish out there, and require ALOT of tank maintanance. Couple this with the fact that people think they can have a Goldfish in a 1 gallon bowl, and you will certainly end up with a dead Goldfish.
3. Fish will only grow to the size of their tank:
Oh so wrong. Fish that belong in large tanks, but are kept in small ones have their growth stunted. STUNTED... This is NOT an adaptation, this is a negative health issue.
(I once had a conversation with someone insisting that he could put Koi in a 20 gallon tank... For those of you who don't know Koi are pond fish that reach 1-2 feet in length. How... retarded...)
4. 1 inch of fish per gallon:
Are you really going to put your 10 inch Oscar in a 10 gallon tank??? I don't think so. This rule MIGHT help you while stocking fish that remain small, but it still isn't a very good rule.
5. Pet stores know what they are talking about:
9 times out of 10 this is false. If you are going to keep fish it is YOUR responsibility to educate yourself on how to do so correctly. The people at the store are there to sell you fish, and that is it. I had a guy try to talk me into buying fish, because he had a chemical that would make the water safe in one day. This is absolutey false. You have to cycle your tank, which takes 3-5 weeks. You must do this regardless of what chemicals you put in.
6. Water changes are not necessary, just top it off:
WAY wrong. Water changes are probably the most important thing you can do to keep fish alive, and healthy. Your water may look clean, but think about this. Your fish pee in the water everyday, all the chemicals you put into the tank stay there until you take them out, and refresh them. Not doing water changes causes all of this to build up, and it will eventually cause health issues/death.
Fish and Requirements/Adult Sizes
Iridescent Shark- As you can see, this fish gets HUGE. I'm guessing it is in a 55g, which is still too small.
Bala Shark: This picture doesn't really give a good size reference, but these guys get about a foot long.
Angelfish- I'm not posting a pic of these, because everybody probably knows what these look like. You could probably keep one in a 30 gallon high tank, but that isn't ideal. You could keep about 3 in a 55g, and you have to have 1 male, and 2 females. They will pair off, and you will have to get rid of the female that isn't paired or she will be killed. In larger tanks 5 plus can be kept, but they MUST be large enough to accomadate breeding.
Gourami- All but the dwarf species get to about 6 inches, but even the dwarf species can't be kept together. I was advised not to have 2 in my 55gallon because they would kill each other.
Well, I think I'm done for now. I do have some updates on my own tank, but I'll save that for later.