Feeding fish?

[BettaMan2000]

One thing I've observed and something I'm a bit worried about when it comes to my turn to get some fish in my tank, is how do they know its feeding time?

The fish in my LFS seem to be fed twice a day but the owner just throws a tiny bit of shredded flake in, for his neon tetras as a case in point, but only a handful of his fish come up to eat at the surface where the food is, the rest of them seem to be doing their own thing at the bottom of the tank?!

I found this confusing, will the rest of the fish starve, as they don't seem to be aware of the food?

This is a bit worrying as I'm thinking of getting some tetras too, but how can you be certain each little fish has been fed properly?

 

[neoyyf]

Throw the food into the flow of the filter. The food will disperse giving everyone a chance. You need the sinking variety for bottom dwelling species. Feed only enough that all is eaten in 2 minutes. If someone did not get food this time, they will eat the next time you feed.

You can have a planted tank and i believe a lot of fish eat a little bit off the plants. Also try live foods, some will escape to the corners and become tasty snacks later on

 

[neoyyf]

I should also add, a fish that does not actively try to grab food is sick, and should be given attention.

At first you may overfeed, if this is the case, scoop out all excess with a net so that it does not foul your water

 

[Byron]

Agree; most of us initially at least tend to overfeed. Fish do not need as much food as we might think, because they are ectotherms, commonly referred to as cold blooded because they do not generate their own heat internally (which takes a lot more food energy) but use the external water temperature (which is one reason temperature is so critical to fish). A tank of healthy fish can easily go a week, even longer, without additional food being added--if they are healthy to begin with, and not fry which need more feedings. Skipping one or two days a week without feeding is a practice many follow.

Now, a trick I learned years ago. When I feed, I gently tap the tank frame with the measuring spoon I use. [I don't actually measure food, but using a small measuring spoon like a 1/2 teaspoon or 1/4 teaspoon is easier to avoid adding too much.] Within a few days, the fish learn to recognize this "signal" as the presence of food. I have foound this especially useful in my tanks with cories and loaches and pleco-type catfish, even otos; these fish may be hidden under plant leaves, wood, rock. When I sound the "dinner gong," within a minute or so out they all come, hunting around for food. It is the best way of observing all the fish when you have some that rarely come out. And you can see by their heightened activity that they are most likely healthy.

Another thing is to feed at roughly the same time each day. Fish also learn this, as they have like all animals a "biological clock" and they can relate activities like food with the period of daylight. Wait for about an hour, half an hour absolute minimum, after turning on the tank lights before feeding or any activity in the tank. Fish need this time to adjust their vision and internal functions are related. I learned years ago that when I fed earlier than the norm, the fish ignored the food, as they just were not expecting it.

Overfeeding is something we must always be careful to avoid. Fish will usually eat if food is present, whether or not they need it. To a degree, underfed is healthier than overfed, as there is some natural foods in an established tank as well as what we provide. And excessive feeding will cause internal problems, not to mention its higher effect on the biological system of the tank; what goes in must come out.

 

[BettaMan2000]

How would you configure that to work with something the size of neon tetras, do I need specific food, I’m planning on keeping a tiny shoal of six in 54 litre tank, they could be in any corner of that tank when feeding comes, and even then I’ve got some tetramin (I’m well prepared, on the advice of the lfs, it’s what they use) that’s a surface applied flake, so how can I ensure the fish know it’s dinner time and more importantly they all eat!

If I stick it in the flow of the filter it’ll get dispersed around the tank to some extent but it’s not even as my filters in the right side of my tank so there’s no guarantee the fish will get it.

Also the fish at my lfs get fed at 10am then 4pm, could I change this to say 12 and 6pm as it’d be a lot easier for me on one day in the week when I need to work the grave yard shift?

 

[NickAu]

Another thing is to feed at roughly the same time each day.

The fish will quickly learn when its feeding time, I feed my fish just after lights on, even my Kuhli loaches have learned that and start hanging out near the front of the tank as soon as the light comes on.

 

[Byron]

Find the time of day that you can use every day of every week, whatever it may be, and stay with that time. When I moveed to my present house in 2000, I had been feeding the fish in the morning before leaving for work at 8 am, but after moving I had to leave before 6.30 and it was still dark. So I started feeding in the evening when I got home, around 6 pm. After a few days the fish expected this. Consistency is the key; fish relate everything to day/night periods. So long as you don't feed too soon after the tank light is on, and in the evening make sure there is a couple hours minimum after you feed before the tank light goes off, you're OK.

The tank lighting should be consistent, every day, without exception. A timer achieves this adequately. Lighting is extremely important for fish.

 

[BettaMan2000]

Thanks again Byron, I’ve got an LED light in my tank but I was scared having to use it as I thought when do I get fish it might be too bright and scare them!

 

[Essjay]

That's another advantage to having floating plants. Not only do they take up the ammonia made by the fish, floating plants also provide shade for the fish. My Espei's rasboras hardly ever venture out from beneath the floating plants.

 

[Byron]

Thanks again Byron, I’ve got an LED light in my tank but I was scared having to use it as I thought when do I get fish it might be too bright and scare them!

This does happen. Tank lighting must not be "too intense" or fish will be severely stressed, and that means poor health, getting various sickness they would otherwise avoid, and early death. Turning the light on and off regularly is also important, and making sure the room is in light when either occurs is also necessary. Here is an excerpt from an article I did on light that will explain.

Fish eyes are not much different from those of other vertebrates including humans. Our eyes share a cornea, an iris, a lens, a pupil, and a retina. The latter contains rods which allow us to see in dim light and cones which perceive colours; while mammals (like us) have two types of cones, fish have three—one for each of the colours red, green and blue. These connect to nerve cells which transmit images to the brain, and the optic lobe is the largest part of the fish’s brain.

These cells are very delicate; humans have pupils that expand or contract to alter the amount of light entering the eye and eyelids, both of which help to prevent damage occurring due to bright light. Fish (with very few exceptions such as some shark species) do not have eyelids, and in most species their pupils are fixed and cannot alter. In bright light, the rods retract into the retina and the cones approach the surface; in dim light the opposite occurs. But unlike our pupils that change very quickly, this process in fish takes time. Scientific studies on salmon have shown that it takes half an hour for the eye to adjust to bright light, and an hour to adjust to dim light. This is why the aquarist should wait at least 30 minutes after the tank lights come on before feeding or performing a water change or other tank maintenance; this allows the fish to adjust to the light difference.

Turning the Tank Light On/Off

When the tank light suddenly turns on in a dark room, fish will dive to the substrate, dash about frantically often hitting the glass sides of the aquarium, or even jump out of the water. The same reactions occur when the tank lights are suddenly turned out. Aside from any possible physical injury the fish may sustain, these sudden changes in the light cause significant stress to the fish. Bright camera flashes can also be stressful in the same way. So also would any unnatural effect such as strobe lighting.

Thom Demas, curator of fishes at the Tennessee Aquarium, defines stress as anything that threatens to disrupt an organism’s normal physical, mental and/or emotional state. The organism must then expend energy dealing with the stressor, which leaves it with less energy to deal with other things, such as pathogens. “If the fish are busy running from or hiding from that weird phenomenon of ‘instant lights on or off,’ they may be wasting energy to this stressor and eventually get sick from something that is most likely ubiquitous and that they would have tolerated had the stressing event not been there,” says Demas. There is now ample scientific evidence that in fish as in humans, stress at any level has a very negative impact on the immune system because it disrupts the physiological equilibrium of the fish.

The solution with tank lights is obvious: the room should always be reasonably well lit when the tank light comes on and when it goes off. As Marc Kind, curator of fishes and invertebrates at the Adventure Aquarium in Camden, New Jersey, says, “this is just good, sound husbandry.” Given the evidence mentioned previously of the time it takes for fish to adjust, the room should be lit for at least an hour before and after the tank light is turned on or off respectively. From my own experience this all but eliminates any frantic reactions from the fish. They will uniformly and quickly swim toward the room light source (be it light coming in the window or from a lamp) when the tank light goes off, but without frantic crashes and jumping into the tank cover glass which will otherwise occur.

The Day/Night Cycle

Most animals have an internal body clock, called a circadian rhythm, which is modified by the light/dark cycle every 24 hours. This is the explanation for jet-lag in humans when time zones are crossed—our circadian rhythm is unbalanced and has to reset itself, which it does according to periods of light and dark. Our eyes play a primary role in this, but many of our body cells have some reaction to light levels. In fish this light sensitivity in their cells is very high.

Previously I mentioned that the rods and cones in the eye shift according to the changes in light. This process is also anticipated according to the time of day; the fish “expects” dawn and dusk, and the eyes will automatically begin to adjust accordingly. This is due to the circadian rhythm.

This is one reason why during each 24 hours a regular period of light/dark—ensuring there are several hours of complete darkness—is essential for the fish. In the tropics, day and night is equal for all 365 days a year, with approximately ten to twelve hours each of daylight and complete darkness, separated by fairly brief periods of dawn or dusk. The period of daylight produced by direct tank lighting can be shorter; and the period of total darkness can be somewhat shorter or longer—but there must be several hours of complete darkness in the aquarium. The dusk and dawn periods will appear to be stretched out, but that causes no problems for the fish. It is the bright overhead light that is the concern, along with having a suitable period of total darkness. And the "day" period when the tank lights are on should be one continuous period, not sporadic, and it should be the same every 24 hours or it will impact the circadian rhythm causing more stress.

The Brightness of the Tank Light

“Daylight” can be vastly different for different species of fish, depending upon their natural habitats. Most aquarium fish are forest fish, living in rivers, streams and creeks, ponds and small lakes, and even ditches and swamps. Some of these watercourses are permanently shaded by the forest canopy or overhanging marginal vegetation; some are filled with branches and sunken bogwood; some watercourses are white-water, full of suspended particulate matter that “soaks up” the light and keeps the water murky and dimly lit; watercourses in full sunlight usually have a thick mat of floating plants, and depending upon the position of the sun in the sky, much of its light may be reflected off the surface. In most areas of the tropics, the rivers and streams rise and flood the surrounding forest for half the year, and it is during this period that the fish move into the even darker forest waters to spawn. For fish living in all of these environments, bright light is something they seldom—and in some cases never—experience, or from which they prefer to retreat given the opportunity. It is no surprise that the fish in the brightly-lit watercourses are almost always found at the edge under overhanging vegetation, branches and outcrops, or floating vegetation.

Programmed by nature over millions of years for such dimly-lit environments, the eyes of a fish are designed to capture the maximum amount of light. This allows the fish to have some degree of vision even in dimly-lit water. But when placed in brighter light, the fish will naturally look for cover in order to escape from that light. Aquarists can readily see this in the aquarium; many forest fish when given the option clearly prefer shaded areas. Baensch & Riehl (1987) called it a “light phobia” in characins. And it impacts the fish’s colouration too.

 

[NickAu]

When the tank light suddenly turns on in a dark room, fish will dive to the substrate, dash about frantically often hitting the glass sides of the aquarium, or even jump out of the water.

Not wanting to be argumentative.

When the light in my tank comes on, my BN goes to his feeding place a small plate and waits for food, The Kuhli Loaches come out of the plants and start looking for food, My Bettas watch carefully to make sure nobody gets fed before they do, Even the shrimp come out for a feed.

In my tanks light on = human has had coffee and food is on its way.

 

[Byron]

Not wanting to be argumentative.

When the light in my tank comes on, my BN goes to his feeding place a small plate and waits for food, The Kuhli Loaches come out of the plants and start looking for food, My Bettas watch carefully to make sure nobody gets fed before they do, Even the shrimp come out for a feed.

In my tanks light on = human has had coffee and food is on its way.

Read in context, the idea is to avoid turning on the tank light in a totally dark room. I guarantee this scares fish almost to death. As will taking photos with a flash.

 

[BettaMan2000]

Thanks again that’s pretty informative!