There are lots of reasons that may lead to death of fish in aquarium tank including the introduction of new fish, little air circulation, introduction of new plants, and poor water quality. Most aquarium diseases can be avoided by ensuring that aquarium water is healthy and neglecting tank maintenance will allow toxins to build up in the water. Rubbing against aquarium decor, hiding in the corner of aquarium, floating at an angle with their fins close to the body, and any white fuzzy spots are the tell tale signs of ornamental fish diseases. Most fish diseases are result of poor water quality and the fish living in toxic water may get more stressed. It is suggested not to overcrowd aquarium tank and acclimate fish to the new tank properly.
The new fish should be acclimatized to the fish tank properly and pH and nitrate levels should be tested accordingly. Test kits are made for testing as well as adjusting the water. Keeping aquarium disease free is not at all difficult and it needs only thorough online research. Tropical fish diseases can be caused by everything ranging from rotten aquarium plants to stress. If a home aquarium has any delicate fish, it is a good idea to quarantine them by putting them into small plastic bags.