[weez1959]

I'm always worried that I'm over or under feeding so the question is, I have a 4" tang that eats 16 square inches (2 pieces of 2"x4" folded and attached to a clip) of nori a day and from what I can see, he would keep eating if I put more. Am I over or under feeding him?

Off topic:
I feel like a complete fool! I went and listened to the LFS clerk once again, jeez I hate those guys! We were supposed to get a larger tank this spring, (never count your chickens before they hatch ) but a new car was in order and the car won over the tank so I traded in the 2 tangs I had for one that would stay smaller. Originally I had a pacific Sailfin and a hippo tang, went though all sorts of trouble healing them from various ailment and traded them in so I could keep up the 75g. Got a Naso instead, he said maximum 6" so I went ahead with the trade, got home, put him QT and looked him up
I for once got up the nerve to call the LFS and tell him that his litle fish would get to be as big as the sailfin but he argued that they don't in captivity...
Anyways, I guess I'll keep him for a few months and see how it goes, he was in QT for about 3 weeks, I did a precautionary deworming in the first few days. He's been in the DT for about 4 days now, still looking good and I think what save him from ich and whatever else usually comes with tangs is that I got him out of the LFS QT tanks, he has them in copper for about a week before putting them in the front so he was saved one acclimation.
Anyways, that's the saga of my tank. At least nobody is sick

[leebca]

Regarding food and quantity. . .

Wild fish tend to continuously hunt for food. This makes them a bit of a problem in the captive life. Sort of like the pit humans have fallen into -- we can produce all the foods we need in North America, so we tend to eat too much of the wrong kinds. Given a limitless feed/food bowl, our fish will overeat.

There are two basic approaches to feeding the right quantity of food. One is more or less scientific and the other is intuitive. Most hobbyists go the intuitive route. Most professional aquarists and many public and private aquariums are run on the more or less scientific approach.

Captive fish don't use up as much energy as wild fish do. Their food is handed to them and don't pose much in the way of having to expend energy to get fed. So a very general rule of feeding marine fishes is to feed about 3 to 5% of their body weight per day. This 'weight' is wet weight (not flake, pellet or freeze-dried foods, but more like frozen, undried algae, or natural foods).

Besides the nutritional requirements I've outlined in this post, Feeding Marine Fish and Fish Nutrition, I also touched upon the quantity to be fed. In public aquariums, the nutrition, variety, type and finally the volume of foods fed are controlled.

Probably the fishes not applicable to this 3-5% daily quantity, are the predatory fishes which eat once, twice or three times a week. There is some tweaking with regards to species and classification (herbivore, omnivore, carnivore) of the fish.

You may find the intuitive approach more manageable and realistic. No matter how many times a day the fishes will be fed, there is an initial 'reaction' to the start of the feeding process. The fish will crowd the feeding area, push other fish out of the way (without threats, since hopefully we have put the right fishes together) and feed enthusiastically. But as the food is dropped in, the fish slow down their response. They may become more selective in what they will swallow or slow down in their attempt to 'get the food.' This is the time to stop putting food into the aquarium.

Many books/writers recommend about 3 minutes. Some have different times. But the point is, it isn't really a timed event as much as it is when the fish have lost their appetite edge. Oh the fish will continue to feed at their leisure if the aquarist continues to add food, but much may be lost or goes uneaten and isn't necessary.

If the aquarist will observe their fish closely, he/she will learn where this 'break' in reaction to feeding occurs, then know to stop feeding.

With regards to Tangs and fishes that like to graze on algae. The concept of intuitive quantity still holds true. When the aquarist first puts in the piece of algae, see how the fish react? In a few minutes the 'second level' of fish may then move in on the algae (if you have a large enough community tank to observe this). In any case, the first 'attack' on the algae will be more or less vigorous and then thin over time.

If the aquarist is smart, add the quantity of algae that will be eaten within the half-hour by the first, second, etc. level of grazing fishes. Do this twice a day in between the other feedings. If only offering algae once a day, then put in the amount consumed in an hour.

When it comes to the aquarist feeding the fish, the weakest in the pair is the human. Don't be fooled by the 'begging fish.' Don't be upset to see the fish beg or to pick at the rocks, decor, and substrate. Be secure in sticking to the intuitive approach.

I've fed fishes for over 37 years. I've had some 'beggars' so intent on begging that as I'm putting in the food, the fish continues to beg for food without even noticing I'm feeding it.