Do you fast your aquarium fish?

Some pond or aquarium fish owners somehow think it is good for fish if they skip feeding a day or two each week for "fasting". I do not do that at all. I feed my fish once every day, seven days a week. There is no skipping on feeding fish from me unless I get an ammonia or nitrite spike from a mini-cycle in the tank.

It is true that fish can go without food for weeks without dying, but I really see no benefit in skipping a day or two even when there is no real harm either.

What is your opinion on fasting a fish? Do you do it? If so, how often?

I knew fish could go a short time without eating but going for weeks sounds pretty extreme for such a small creature. When I have fish, I feed them daily but my grandma had fish that she fed every other day. She said that feeding them daily would kill them (I don't think that's true as I've had many fish and feeding them daily never seems to hurt them).

I haven't tried using this fasting method on my fish. However my friends who rear Arowanas tell me that fasting keeps the fish in good health and in good shape, too. They say it's good to feed the Arowana only once in a couple of days.

(08-27-2012, 10:51 AM)writer811 Wrote: I knew fish could go a short time without eating but going for weeks sounds pretty extreme for such a small creature. When I have fish, I feed them daily but my grandma had fish that she fed every other day. She said that feeding them daily would kill them (I don't think that's true as I've had many fish and feeding them daily never seems to hurt them).

Actually fish use very little energy to stay alive. I think you are thinking on a mammal/bird term. Mammal and birds need to keep body heat, which cost a lot of energy just to stay alive, thus both must eat a lot. Fish is cold blood animal, they don't need to eat that much. Fish's stomach is also as small as their eyes. Overfeeding is one of the top causes for fish deaths.

It is also proven that fish can go for 3 weeks without eating anything at all. Even humans can do that as long as they drink plenty of water. Of course, it is not recommended to try.

I have skipped feeding on a few occasions when there was a problem with water quality. There was no ill effect. However, I really don't see fasting fish bring any benefit when it's done on a regular basis.

The chance would be a fine thing with our fish! Every time my husband goes near the tank, they all come over to him, expecting to be fed. Of course, they don't get fed, but it doesn't stop them hoping. When we go away, my neighbour comes in to feed the fish, and I tell her to skip feeding them once if we're away for two weeks, and twice if we're away for a month. It gives her a break, and it keeps down the snail population when my husband's not there to hook them out on a daily basis.

(09-18-2012, 05:10 AM)Sandra Piddock Wrote: The chance would be a fine thing with our fish! Every time my husband goes near the tank, they all come over to him, expecting to be fed. Of course, they don't get fed, but it doesn't stop them hoping. When we go away, my neighbour comes in to feed the fish, and I tell her to skip feeding them once if we're away for two weeks, and twice if we're away for a month. It gives her a break, and it keeps down the snail population when my husband's not there to hook them out on a daily basis.

Sorry I have to point it out. You are definitely overfeeding. Pest snail population explodes when there is a surplus of food in the tank.

I have had this problem several years ago, and it was gone with the combination of cut back on feeding, and the use of assassin snails to eliminate them.

For the cut back on feeding part, I had to make sure there is no leftover food in the tank as soon as the feeding is finished. The usual amount of food I feed will only last less than 30 seconds in the tank with nothing left by the end of that 30 seconds.

Thanks for that, Ram. I told Tony he was feeding them too much, but he wouldn't believe me. Now I've shown him this, he's putting them on a diet! He's also going to get some assassin snails - it appears to his base nature. Thanks for the advice - we appreciate it.

I have never fasted my aquarium fish before. There have been times where I have been on vacation for a weekend and they haven't eaten, but I have never intentionally not fed them. I wonder what the purpose of this is? My thought is, is that fish are not always hungry and they may not eat the food that is given to them right away. So, what happens is that the food goes to the bottom of the tank and probably makes the tank pretty dirty after a while if the food is not ate right away.

(09-18-2012, 11:46 PM)dashboardc33 Wrote: I have never fasted my aquarium fish before. There have been times where I have been on vacation for a weekend and they haven't eaten, but I have never intentionally not fed them. I wonder what the purpose of this is? My thought is, is that fish are not always hungry and they may not eat the food that is given to them right away. So, what happens is that the food goes to the bottom of the tank and probably makes the tank pretty dirty after a while if the food is not ate right away.

Some people believe fast fish - skip a day or two feeding each week, can make fish more healthy. Although overfeeding is one of the top causes for fish dying in home aquarium, I personally do not believe fasting brings any benefit.

No, you should never see fish food at the bottom of the tank unless you have bottom feedings who will chew on them right away.
In a healthy aquarium, fish should be all come to food immediately after you drop it into the tank.

Never leave leftover food in the tank ever.

I do not personally believe in fasting, or see it as having any big advantages by itself. Still sometimes I will fast my fish for a variety of reasons. When I go on vacation, I often fast them, because if I get an auto-feeder, there will be waste and no one there to clean the water. Also, if I am very busy one week and do not change the aquarium for my water, I may fast them, because it results in less waste, which keeps the water a lot cleaner.

However, with that said, I still have yet to see definitive proof or results that fasting fish for a week or two at a time really helps them with anything.

If fish are correctly fed there is no reason to fast them one or two days a week, although many will recommend it. Fish have no stomach as such, the food is digested as it passes through the gut on it's way to the anus. While they seem to take food every time you feed them, (feeding frenzy), partially digested food is passed out. This then starts to break down and decay in the tank, producing excessive load on the bio system.

That said, when ever we used to go on holiday, a few days or a week, I never used auto feeders or got a friend to call in and feed them. There was no need. All my tanks were heavily planted and if the fish got hungry enough they would nibble on the plants and algae. When we returned the water always appeared to "shine" it was that clean, and the fish looked as healthy as could be.

(02-01-2014, 10:24 PM)TheBrit Wrote: Fish have no stomach as such, the food is digested as it passes through the gut on it's way to the anus.

I have to disagree. I guess you have not seen a cut out fish before? I have. Nope I did not do it in case you wonder.

Fish have stomaches. It is as small as their eye when it is empty. Yes, it can be stretched to be much larger when needed, but it is unhealthy to them. You only need to feed the fish once a day and as much as it can eat within 30 seconds if there is only one fish. Make it a minute if you have a tank full of fish. The rule does not apply to bottom feeders such as corydoras catfish who are relaying on large algae wafers.

I find the idea of fasting fish a sort of an aberration. Granted, it would result in less waste but then fish don't have much energy reserves since their bodies store little fat. A fish is a small animal which means it has a large surface area to volume ratio. Such animals need constant feeding to replenish their energy requirements as opposed to bigger animals with a bigger volume to surface ratio which is more effective in conservation of energy in the body. In any case, I think this would result in hypotonic conditions in its blood. I posit that fish are delicate creatures and something which is out of the ordinary should be seldom tried. The nitrogeneous waste which they excrete into the water is also important in the ecosystem because it enables the survival and growth of water plants like Elodea. Fish are also filter feeders and do feed on dead organic matter in the water called detritus which is more or less always present. This means that the idea of fasting fish for a few days especially when you are absent is not true to fact. At the end of the day, nature has a way of correcting itself through positive and negative feedback mechanisms.