Actually, it probably has more to do with the fact that the tanks weren't cycled, and the ammonia levels got toxic. It's actually not a good idea to buy a new tank and drop fish in - the tank is not ready for them yet. Being new, (which I'm also somewhat), you should probably get to reading up about the Nitrogen Cycle right away.
And you'll need to get a test kit, a liquid one, right away if you have any remaining fish. If you choose to put fish in soon after establishing the tank, what we call a Fishy Cycle, it'll mean regular water changes, as often as necessary, to keep that level below .25 ppm!
If you don't have any left, I recommend taking it slow, and doing plenty of research on the cycling process, so you'll be knowledgeable and prepared, and have it down before the next attempt. (And if you don't have any survivors, most here will suggest Cycling without fish. Check out all the Stickie threads having to do with cycling, and do searches. There is plenty of information available.)
I would also suggest to anyone reading this that the first time something doesn't go the way we hope it to, that is the best time to start asking questions. Because without changing anything the second time around, the results of the second attempt were probably going to be exactly the same. (Fatal.)
Also, as you'll find out, most fish keepers try to avoid chemicals whereever they can. They usually only add one thing to new water, and that's a dechlorinator/chloramine remover. (Tap water contains chlorine and other harsh chemicals, so it requires the use of a product like Prime to remove that and make the water safe.) I think it's possible that one of these chemical products plus so much ammonia from the fish (poo-ing themselves to death) may have yellowed the water. But it's only a guess since I don't know what those chemicals were.
Sorry your start has been so rocky, but you have plenty at your disposal to learn from and keep happy, healthy, long lived fish.
Are there any fish alive still?
