Feeding:
Feeding fish might seem easy, but it is actually one of the most difficult things to teach. In my 35 years of being in the commercial fish business, I have rarely run across an employee who knows how to feed fish properly. It is necessary to have the sense of awareness not to overfeed or underfeed. In some ways it is as much an art, as it is a science. The first rule of thumb is: when in doubt, underfeed! If necessary you can always rectify the situation later by increasing the feed amount. However, if you overfeed, then eventually you can run into some serious problems.
While most hobbyists usually overfeed their fish, there are also those that underfeed their fish to such an extent that their fish actually look anorexic. Many reef keepers are guilty of this due to phosphate and nitrate concern. If the fish is truly fat, simply withhold food and feed less. If the fish is too thin, simply feed more. A hobbyist should know that he or she is in control, not the fish. A healthy fish will always beg for food, but if the fish shows no interest in food, chances are you have a big problem. Either they are sick, or in very bad water conditions.
When you feed pellets, the correct size is very important. Large fish can eat small pellets, but if the pellet size is too large for the fish, they will usually spit it back out, or expel a large portion of the pellet into the water column while chewing. The key is to use a pellet size that allows the fish to swallow it whole. If you keep a mixture of fish sizes in the same aquarium, you can mix different sizes of pellets to ensure that all of the fishes receive their fair share.
Another common mistake by some hobbyists is to pre-soak their pellets, in the misguided belief that this will aid in digestion and prevent swelling of the pellets inside the fishes gut. This is nothing more than an urban myth created by those that simply do not understand the amount of enzymes and gastric acids that are released by most fish when they consume food. Those hard pellets turn into soft mush in a very short period of time! If a pellet food causes gastrointestinal issues in a fish, it will usually be due to the use of poorly digestible ingredients, such as excessive amounts of grains and grain by-products, not from the food swelling up inside the fish's stomach. Most importantly, when you pre-soak pellet food, you are allowing nutrients and water-soluble vitamins and minerals to leach out into the water.
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