How large is the aquarium? As the other poster mentioned you should look into the nitrogen cycle to understand what happens with food and waste in an aquarium. Ensure you're treating fresh water with dechlorinator, etc. That said, the people at Nebraska aquatic supply are knowledgeable and should be able to provide good advice.
It seems to me your aquarium is not cycled yet which mean it dosen't have enough good bacteria to consume the ammonia in the water how long has the aquarium been set up for? and how is your aquarium set up do you have a filter?
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