Over the past few years there have been significant advances in just about every aspect of taking care of the inhabitants of our reef tanks. There has been a significant increase on providing the proper nutritional requirements of our corals and other sessile invertebrates. As a result, a plethora of foods and additives are now available to help maintain invertebrates that up until recently were thought to be impossible to keep for the long term.
No longer is the general consensus that all you need to keep your invertebrates happy is good light and fish poop. While I have read countless articles on this subject, I have come to realize that while this improved knowledge has been coming about, there has been little written about proper feeding and the nutritional requirements of our fish. While I know that for many of us the fish in our tanks are kind of second class citizens so often we take for granted that all we need to do is put in a clump of flake food or mysis shrimp daily and all will be well, but obviously there is more to keeping our fish healthy for the long term than that.
What really brought this to my attention, was a recent visit to a friend’s house where he had set up a nice reef tank about a year ago. It was his first tank, a large soft coral tank containing lots of fish. The tank had been doing well up until a month or so ago when there was suddenly a huge algae outbreak. When I went over to see what was happening and test the water he had an astounding 2.5 ppm reading for phosphate and a 100ppm level for nitrate.
We tested everything from the water coming out of his RO/DI unit to his salt, checked the skimmer, etc, but we could not come up with a reason why his levels had gotten so high. Then I asked him a simple question: How often are you feeding the fish? He said he and his wife only fed the fish “when they looked hungry”. I then asked him: how could he tell? He said it was easy when he or his wife walked into the room the fish would swim toward them and this told them they were hungry.
This made me laugh when I told him they weren’t feeding them when they were hungry, but rather that the fish had trained him and his wife to feed them every time they walked into the room by making them think they were hungry. In this regard the fish were smarter than he and his wife. This made me think of the first thing I was told when I set up my first tank: Don’t overfeed your fish! It was true then and it’s still true today.
So this then begs the question: What is the best way to feed our fish? If you go online many sites offer this simple and straightforward answer: “Once a day is fine and as much as they can eat in five minutes”. This may have been fine when one was keeping a 10-gallon tank full of guppies, but the rare and expensive fish that many of us now keep in our reef tanks deserve and require a better understanding of how and what to feed them than this.
So after now keeping some fish for five, ten and even fifteen years I think I have learned at least a little something about feeding fish properly. I wish I could say I was always successful, but from time to time I will get a fish that will refuse to eat or one that will stop eating and as a result I will lose it, but for the most part I have gotten pretty good at getting fish to eat and keep eating.
The first step in proper feeding is getting new fish to eat. Every new fish I get goes into a quarantine system to not only get it acclimated to the water conditions in my tank, but just as important to get it eating. Most of the fish I have lost over the past 10 years were due to my rushing them into the main display tank before they were adjusted to eating in a captive environment. So every new fish is given a month or two to adjust to eating a captive diet.
In this regard I try to at least initially feed it foods similar to what it may eat on the reef. If it has a small mouth, like an anthias or small pseudochromis it is fed small plankton-like foods. If it is a grazer like a tang or an angelfish, the herbivore based food is rubbed onto a piece of rock so that it mimics how the fish normally would eat. For fish that pick microfauna off of rocks like mandarins and scooter blennies live rock from my tanks or sump that have copepods and amphipods on it are regularly rotated into their tank. In this way I try to slowly acclimate them to a captive diet.
I also try to determine where the fish is from and for the first week to ten days the lighting schedule on the quarantine tank is close to what it was where the fish came from. During this time the light is gradually shifted to when it is on in the display tank. From a feeding perspective the fish are fed when they would normally be eating had they still been in the wild. So for some fish this may require my feeding them in what is the middle of the night for me, but is the middle of the day for them. I also try to find out when these fish would normally feed in the wild. For example some anthias and fairy wrasses feed heaviest at sunrise and sunset, when the plankton levels are highest. So these fish get fed heaviest at these times in the quarantine tank.
Once the fish are acclimated to a captive diet and acclimated to the water conditions and are relatively fat, only then are they added to the display tank. I’m not going to get into my acclimation procedure here, other than to say I try to make sure that the bullying they are likely to encounter will be minimal as one of the causes for a fast demise in a fish is bullying that keeps it from eating. The fish in my display tank are all well fed, as the tank is fed 8 times per day. This may seem like a huge amount of food, but the feeding are all relatively small and also they are contained.
When I say that they are contained, what I mean is I try not to have the food shot all around the tank due to the high amount of current in the tank. In order to do this I employ a feeding chimney. This is nothing more than a clear 4-inch diameter tube that is ten inches long, that I used an old reaction chamber. The top hooks on to the edge of the glass and the food for the fish is either dumped into it via an automatic feeder or when I feed the fish. In this way, the food stays within the tube and the fish have come to learn to pick off the food as it flows out. In this way, food is not wasted nor does it get blown to the recesses of the tank where it will decompose.
The fish are fed a variety of foods in various shapes, sizes and textures to try and mimic the variety of food they get on the reef. Feeding eight times per day also more closely mimics how they feed on the reef which is almost constantly for some fish. Also surprisingly, this feeding small amounts often has reduced the nutrient levels in the tank as the fish apparently are better able to metabolize what they have eaten better than was the case when they were getting one or two large meals per day.
Lastly these small frequent meals also increase the likelihood that every fish in the tank will get some food during the course of the day as the randomness of the feedings means that every fish at some point will be near the chimney when food is being dispersed. I have also read that this type of feeding schedule reduces the likelihood of fish getting fatty livers, which may occur when they only eat one large meal per day. I do not know how true this is, but I now have kept my marine betta for over 15 years and my Red Sea Regal angel and yellow tang are going on 12 years in captivity.
Some of the foods I feed the fish are mysis shrimp, cyclopeeze, ocean plankton, several of the commercial mixed fish diets, grated or chopped shrimp, chunks of flounder or cod, numerous pellets and chopped nori and other seafoods in the automatic feeder and a commercial herbivore diet that I mix myself. As with humans, a varied diet is much more likely to be consumed than is one that only contains one item.
The total amount of food for the 50 fish in my 300-gallon tank is around 40-50 grams per day. This is approximately the same amount that used to be fed in one or two feedings, but now it occurs over 8. Feeding your fish should not be a chore, and can be fun as your fish get to know you. However you should also not let your fish train you to feed them all the time. When done properly and with some planning, it will allow you to keep your fish alive and healthy and in a healthy environment almost indefinitely.
If you enjoyed this article you might also like this article by Matt Pedersen on how feeding frequency affects fish behavior and health