What do fish eat

Discussion in 'General Discussions and Advice' started by Paul B, 30 Mar 2011.

  1. Paul B

    Paul B

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    Just some of my observations:
    Oddly enough fish in the sea do not eat flakes, bloodworms, mosquito larvae, mysis, brine shrimp, squid tentacles, fish fillets, or pellets.
    They eat what they were designed to eat and they only live in the areas where those foods come from. If a fish is in the one or two percent that is lucky enough to actually makes it to adulthood it probably means that it has learned a couple of things, one is to evade predators and the other thing is to find the food that it needs every day and not just once a day.
    Most fish eat a very little bit all of the daylight hours and the rest eat only at night. Having good eyesight is not as big a deal for a fish as it is for us. They get along quite well with just one eye or in total darkness and they have evolved to eat a certain type of food that it needs for its particular physiology.

    A fish like a mandarin was built to take advantage of a food source that most other fish of that size will not even notice. But such an active fish as a mandarin needs a lot of food and just about all it can eat are pods and other creatures about the same size. Pods are invertebrates and therefore mostly shell with a little “pod meat” inside. Pod shells are mostly chitin like our fingernails and have almost no nutrition except for maybe some calcium. In this hobby we call any tiny creature a pod or copepod but in reality these creatures in our tanks and in the sea are mostly an assortment of tiny larvae of larger crustaceans such as crabs and shrimp but some are bonified copepods.

    Other fish such as tangs live on fresh seaweed or algae. Algae grow on all healthy reefs but because of all the herbivores we usually don’t see it. Luckily for these animals it grows very fast but they had to develop jaws and teeth to take advantage of this paper thin quantity of food. As they graze on algae they also pick up any pods, worms, slugs or inverts that happen to also be grazing on the algae. This “by-catch” is important to the health of these fish as it supplies other nutrients that are missing in algae.

    Fish with long snouts like Long Nose Butterflies and Copper band Butterflies evolved to take advantage of a food source that resides in holes in rocks. These snouts are a disadvantage to these fish when it comes to defense or swimming because their jaws are weak and fragile. Their teeth are very small to fit in such jaws and are only suited to eat small soft foods like worms and tiny shrimp.
    These types of fish need a large part of their diet to be oily like worm flesh is and is one reason these fish do not live as long in captivity as many other fish.

    Most other fish in the sea eat whole fish. If you do any diving in the tropics and you look closely near the bottom you will see multitudes of tiny fry. This is the main source of nutrition for many fish. All fish have a liver which serves two purposes. The main purpose is the same reason we have a liver, to cleanse our blood but the other reason is buoyancy. Oil is lighter than water and the oil in their liver allows the fish to be almost neutrally buoyant. Their swim bladder is used for more delicate adjustment of buoyancy but the liver is the main organ that keeps fish from sinking like a rock. Without a liver and swim bladder even us humans would be able to swim better than a fish because we have quite a lot of air spaces, fish do not.

    This fish oil is also invaluable to a fishes health as fish do not have fat like mammals.
    Being cold blooded animals a fish can not utilize fat because it would remain solid at the temperatures in a fishes. Out 98.6 degree temperature allows up to eat solid fats.
    (But fish oil is also much better for us to eat in small quantities in stead of solid fats)
    Also when a fish spawns, almost all of that spawn is oil. Oil is what nourishes a new born fish until it is able to hunt on its own.
    When a fish is in spawning condition it also has a super immune system as many animals in that condition have. It takes a large toll on a fish to produce eggs that could be a quarter of the fishes weight. Much of that weight is oil and most of it comes from eating whole fish. They can produce some of it on their own but it is much easier on the fish to be able to eat a diet high in oil.
    If a fish eats another fish it gets about 25% of it’s meal in the form of pure fish oil just which is just what it needs to produce eggs and rev up it’s immune system.
    Fish in spawning condition are “almost” immune to most diseases.
    When a fish eats another fish it also gets calcium from the skeleton and all the vitamins and minerals in the correct proportion that a fish needs.
    In the accompanying photo taken in the Caribbean you can see tiny fry to the left of the nurse shark. Those fry are all over the place and almost all of the fish take advantage of that easily acquired drive through fare.

    [​IMG]
     
    viper357, Reef Maniac and archiecrain like this.
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  3. seank

    seank

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    Very interesting, never thought of it that way. Thank you for sharing
     
  4. gMAN

    gMAN with the plan

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    :thumbup: for sharing....interesting indeed....
     
  5. durleo

    durleo

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    It is funny you should bring this topic up - I used to feed a homemade Frozen mix with norrie , Seafood , lemonjuice and garlic and I supplement it with Tropic Marines Lipovit and Immunvit with Spirulina and COD liver oil and my fish where always super healthy. I have always had whitespot in the tank but it never proved fatal for any of the fish. Recently I had to cut down on the nutrients cos my DSB was upset so I stopped feeding this mix for atleast 1.5 months and only fed flakes and norrie. My fish now have visible whitespot and I have just started feeding the mix again so will monitor their health now.;)
     
  6. erle_vaughan

    erle_vaughan

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    You got a little recipe to share?
     
  7. erle_vaughan

    erle_vaughan

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    awesome post @Paul B
    easy reading and full of info.
     
    Last edited by a moderator: 26 Nov 2015
  8. Reef Maniac

    Reef Maniac MASA Contributor

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    Excellent info :thumbup:

    Mods: this post needs to go in our articles section

    Hennie
     
  9. Jeann1

    Jeann1

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    Very nice read, thank you.

    What about all the Ocean Nutrician products ?? I buy all the different products, add the vitamin c powder suggested in the home made mix thread, add spirulina and garlic to it, and then feed to my fish..
     
  10. Prash06

    Prash06

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    Very nice read man! I always wondered how important is oil in their diet. Guess this answers it. Gonna try out that cod liver oil and garlic like Durleo once I get the tank sorted and some fish.

    Thanks man :)
     
  11. Suhayl

    Suhayl

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    Hi Paul, how many times a day do you feed your fish? Are you fishing still spawning all the time?
     
  12. Boegie

    Boegie

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    Great info thanks Paul.
     
  13. Paul B

    Paul B Thread Starter

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    Suhay, I usually feed twice a day. Once with just some live worms and the other feeding with some more worms, clam, plankton or whatever else I have.
    For most fish I recommend a diet high in fish oil. There are two fairly easy ways to do this. Of course feding small saltwater fish would be a perfect diet but these are not sold commercially and I don't know why. I spoke to "Ocean Nutrition" about this and they were supposed to send someone to my home to talk about it but I never heard from them again. I even know a source for very tiny makeral but I only see it dried and it has the consistancy of wood. The fish eat it but it is hard for them to swallow as it needs to be soaked overnight.
    I feed live blackworms every day as they are very common here in NY. I built a worm keeper and they stay alive indefinately. I don't make the worms the entire meal as fish also need greens and calcium.
    I also soak soft sinking pellets in fish oil the same kind of oil I myself take. I use these for the spawning gobies I have that tend to stay in the back tending their eggs and almost never venture out any more.
    Sometimes I soak flakes in fish oil. I put a drop of oil in a little water and shake it up. It makes an oil slick. Then I float some flakes on this and feed it to my tangs. Don't throw in that water or the oil slick will stay a couple of hours. It will disolve but it will also stop your skimmer for a few hours. Fish eggs are also extreamly good and they are sold fresh in Asian stores. Salmon eggs are about 1/4" and great food, probably the best thing for fish, anamones and LPS corals. They need to be rinsed very very well or your skimmer will overflow gallons.
    People ask why oil is not included in commercial foods, that is easy. It goes bad in the presence of oxygen and even freezing does not keep it well. That is why it is sold in capsules and no longer in bottles like my Mother used to make me take. Cod Liver Oil, Yuck
     
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