How Much Do Fish Actually Need To Eat?

[dilbert]

Hi all,

there is often used the term overfeeding, but I couldn't find anywhere some figures how much to feed actually to different fish of different size and age.

With tortoises, for example, there exists the concept of the "leafy jacket" that means the equivalent in size of vegetables or weeds compared to the size of the tortoises carapace. Even this concept is very vague as someone usually doesn't take into account how much compressed this green stuff is.

For me now, overfeeding is when the next day there is a small spike of nitrite (0.25 ppm) and nitrate (10 ppm usually) in tanks where normally all three figures (ammonia, nitrite, and nitrate) are zero.

I started fish keeping only three month ago and to me those fish seem always to be hungry. They might get fed up easily with one food but then take on eagerly another food a short time later. As an example, today I fed frozen Mysis shrimp to a tiny (3/4 inch) Blue Damsel and an one-inch Clownfish. The Damsel took about five pieces and the Clown three. Both fish then discarded the left over pieces, but a few fish flakes throwed in half an hour later were taken again by the Damsel, but spit out by the Clown.

Is there something like 5 to 10 pieces of frozen Mysis shrimp, or 10 medium-sized fish flakes or half of a one-inch-long raw shrimp, or anything like this?

 

[1entra]

No there is nothing specific in the way of feeding. But you are only suposed to feed enough so that your fish will consume it in about 1-2 minutes. If there is food still left floating in the water then you are overfeeding by adding too much food so next time feed a little less. All leftover food should be netted back out of the tank so it does not pollute the water quality as you should not have any spikes on your nitrites or nitrates after feeding!

Personally I feed a tiny pinch of flake food to my fish and wait for them to finish eating it before adding another small pinch. I do this several times till I beleive it is enough.

It is always better to underfeed the fish than to overfeed them, as in nature fish may eat something one day and not find no more food for several days, so their bodies can easily survive without food for this period. For this reason fish will contine to pig out when food is constantly given to them as their natural instincts tell them to eat up whilst food is plentiful as they may have to fast for several days after when food is not so readily available!

I feed my fish once a day but have friends that feed once very other day and some that will feed their fish tiny amounts through out the day every day! It all seems to work well but you have to adapt a feeding approach that both fits in with your schedule and does not pollute your water due to overfeeding!

 

[chrissaysyes]

I over feed my nano, mainly because water changes are so frequent and simple, also because I like to make sure my sea star gets plenty.

 

[dilbert]

Nitrite spikes (I never get ammonia spikes in both tanks) I am getting only if I really give three cubes (of the size of a sugar cube) into the tank or other stuff way to much in an attempt to find out what some particular animal prefers to eat. In a way like "let's try this and that ...". Surely, that's stupid but happens only with a new animal.

But normally, a single cube or two don't produce any spikes. Today, I fed again the frozen mysis shrimp and that stuff must be really bad, as almost nothing has been taken by anybody.

The stuff floats like snowflakes through the tank for 15 minutes and after half an hour everything has entirely disappeared. The sand bed looks like a desert. I don't have any real detritus eaters. Also, I have never spotted any mobile critters from the live rock, not even at night with a red lamp.

I am really astonished how all this left over food disappears. It must get stuck in the porous live rock and I don't know if it gets eaten there by some cryptic critters or simply gets decomposed by bacteria.

Back to the frozen mysis shrimp. Even the platys in the brackish didn't want them today. And the platys eat almost everything. The platys turn later when the dinner is over to real detritus eaters and finish then off what they left over earlier. They turn the gravel around, eat algae and suck in stuff from the surface of rocks and leaves. Together with the Amano shrimps they clean up their tank themselves.

So, in none of the tanks I have problems with detritus accumulating.

The thing to learn seems to be feeding sparsely and look if it's taken or not. I was mainly concerned as I have only juvenile fish that may need a more constant feeding scheme to thrive. Varying the food often seems to be the key.

 

[svirid]

I started just 4 month ago, for now I have only Cardinal in my tank. he eats only Mysis or Brine shrimp, does not want to eat any dry food. I have no idea how to feed fish, never had fish before but here is what I do.
I know that to rid of the Ammonia or nitrite in the tank could be very hard (without chemicals, thats how I am trying to have my tank, no additives at all, only phospate remover), anyway its better to have fish a little hungry then overfeed.

So I give him 2-3 portions of shrimps apx 3-5 pieces each, I am not waiting until he stops eating I am just looking when he slows down while catching a food, I think it means he is not that hungry anymore. After that I have fireshrimp running like hell for a next hour collection all leftovers, also I have 10 nasariuses that are getting out of the sand as soon as food touches the water.

Anyway thats the way I do it, maybe its wrong but atleast I have my water parameters in 0.

 

[dilbert]

The Clownfish I got is about one inch long and the Blue Damsel is about 3/4 of an inch. The Damselfish eats about four times more than the Clown.

The Clownfish is very picky. Firstly, he doesn't look that actively for food. I don't know why he is always swimmimg around. And often he only takes pieces into his mouth to spit them out immediately.

But today he ate at least one piece of frozen bloodworm and a tiny piece of raw prawns (that we have later prepared for ourselves).

I was only wondering how the Clown is swimming the whole day around and eats only a few pieces but I presume he ain't hungry if he spits out the most part of it.

I tried now so far, with garlic and without:
- seaweed
- frozen: mysis/brine shrimp, bloodworms
- live: brine shrimp, daphnia, bloodworms
- fish flakes
- raw: prawns, shrimps, cod (as we eat much seafood of all sorts there is more to come)

He eats from everything a little but never more than two pieces during a day.

 

[Lynden]

MArine, and especially reef, setups can, in my experience, adapt somewhat to a certain level of feeding. My entire tank gets a half a cube once or twice a day, and though much of the food escapes into crevices I suspect it is eaten by isopods, whelks and bristleworms.

I also feed the morays a giant prawn (between them) about once every three days, and when they appear in the clearings of the tank. Essentially, they decide when they get fed; but, the caveat with this method is that nearly all fish learn to beg for food, and some, such as lionfish and frogfish, can even eat themselves to death if enormous amounts of food are given as it rots in their stomachs.

I also typically feed the large anemones every three days but I have severely reduced this to "clear their systems" and attempt to get them to expand further during the day.

As evidence to the first statement, my marine tank has a monstrous bioload and yet manages to stay in very good condition. They can adapt by some degree, through the proliferation of 'pods, bristleworms, bacteria and other organisms, but if the feeding pattern is changed quickly, one can expect nutrient spikes.

 

[chrissaysyes]

Off the subject but to Lynden, you really need to post some more pics sometime soon. I want to see the new nems!

 

[Lynden]

Er... yeah. The owner was getting rid of them so I said, "hey, pass 'em my way" and I thought I was getting an extra nem or two. Running late, I phoned to let him know I was gonna be a while and he then told me that he had 5 more nems in a bag. So, I took them, happy but perhaps a little worried.

They were a mix of fat tentacled and thin tentacled nems, and the fat ones are really doing well; and it shows. Their (two of them) pastel colours make everything else in the tank look dull, and every day the largest fat one expands to shade many of the other sessile animals. The thin tentacled ones took a bit of a fall, and indeed one is hiding now, but are rapidly regaining former vibrance and fullness.

So, basically when I said I needed to cram five more nems into my tank on your first starfish thread... I wasn't joking.