What do fish eat - The Reef Tank

Go Back   The Reef Tank > Livestock related Forums > Reef Fish

Old 03-30-2011, 01:11 PM   #1
Paul b
Paul b's Avatar
Join Date: Mar 2010
Location: Long Island NY
Posts: 3,741
What do fish eat

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.

Paul b is offline   Reply With Quote
Sponsored Links
Old 03-30-2011, 01:42 PM   #2
Little Fishy
Join Date: Mar 2011
Location: Mid MO
Posts: 149
So if we should feed them live food, is there anything wrong with feed live brine?
My Specs
One Day at a Time...
aborgardt is offline   Reply With Quote
Old 03-30-2011, 02:24 PM   #3
The camaro loving reefer
dmora723's Avatar
Join Date: Aug 2010
Location: Near The Motor City!
Posts: 3,809
Images: 13
Paul i always enjoy reading your thread.
but my view is a bit different. i use to live on marathon key, 2 miles from a great reef. i spend every day out there, studying what goes on.
a few of my dives i brought some food with me to provoke a feeding frenzy. my goal was to lure in some bull and tiger sharks. so i could watch them, stupid i know, but i was sick of only seeing nurse sharks. i started with frozen brine down on the reef. this attracted smaller fish like damsels,an blennys and such. than i took out the squid chunks and this got the attention of the scats (sp), and drew in the barracudas, and king fish and Spanish macs (i never thought i would see king fish on this reef.). my brother kept on feeding squid from the boat, while i was underwater at a safe distance.
a green moray came up for some food, but was to scared to swim to the surface, and only got scraps. (these scare me more than any shark). i got out of the water after about 40 mins of this. the Girl friends continued to feed the fish for about 30 mins, while my brother started fishing for bigger bait. now with a few snappers floating on the surface, (still planed on eating them, if a shark did not) and what do you know, a pair of bull sharks made there way to the reef. i garbed my speargun and mask and dove in with out tanks, nor weights, or BCU or fins, and watched as the pair started eating these little bits of squid. (we cut long triangles about 2-3 sq inches. i could not believe my eyes as i watched two 10' or larger sharks eating little bits from the surface.
my point. the hole reef came out that day to eat the "fish food" i was feeding them, and almost every species eat it. besides angels and parrots.
this troubles me, because fish keepers learn from an early age that wild fish need to be taught to eat fish food. and really thats not the case, i think stress is the major issue on why wild fish do not eat fish food.

now you may say that squid is not general fish food, but i have been feeding it to my Oscars for years, and i know others.

quick other story. when fishing for ballyhoo i used formula one pellets (medium size i think) and they came right up and eat it with out a problem.

but i will strongly agree that FRY is a major food source on a reef. thousands upon thousands of fry is born per day on the smaller sized reefs. i have been feeding convict fry (use less) to my SW fish for years. they love it. and the convicts are hardy enough to live in the SW for about 30 mins at 2 weeks old.
~Nic~ YFR Current major: Wildlife Bio. Long term major: Marine Conservation Bio & Zoology. EMT "Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science." -Darwin
dmora723 is offline   Reply With Quote
Old 03-30-2011, 04:21 PM   #4
Paul b
Paul b's Avatar
Join Date: Mar 2010
Location: Long Island NY
Posts: 3,741
Dmora, I did not mean that our fish will not eat squid, flakes, mysis and brine shrimp, I meant that they will not be the healthiest they can be on these foods. I have also brought food down to feed fish while SCUBA diving (many times) and it is true they will eat just about anything, but the food they normally eat when we are not feeding them is what they need to stay healthy. Even bull sharks need a specific diet which is about 20% fish oil that comes from the fish they eat. In captivity sharks can be fed scraps of fish and squid but they need whole fish. Fish fillets, squid and shrimp is severly lacking in oil. It only comes from whole fish (and worms)
A copperband butterfly in the sea would never be able to eat a squid. If we chopped it up in tiny pieces it will eat it but it will not live a long healthy diet on that food. We don't want our fish just to live, we want them to thrive and be resistant to disease like they are in the sea. In my 40 +years of diving I have never seen a sick fish. Why? Because they are all in breeding condition from eating the foods they were designed to eat.
I personally do not have to quarantine and have not in decades. I have not had a fish die from any disease in that time either. I attribute that to the diet I give them which is rich in fish oil. Every day they get live blackworms and pellets soaked in fish oil. They also get those other foods I mentioned but I want to get oil into them every day.
My fish also do not get ich. I add animals from the sea along with mud, seaweed, worms, shrimp, barnacles and sponges and I buy livestock from many different places. I know there is ich in my tank but it does not affect anything. The fish live long enough to die of old age or more usualy in an accident like being chased and jumping out. Unfortunately, healthy fish breed or try to breed, in that condition many fish do not tolerate other fish and chase them from their nesting ground.
If fish are not protecting nests, they are not that healthy and not immune from disease. Of course not all fish will breed in a tank but the ones that will like damsels including clowns, gobies and bleenies will all protect nesting sites and chase other fish.
Fish in our tanks should never get sick and IMO it is due to their diet, or lack of it.
PS Adult brine shrimp are not a good food at all and should not be used. They are not even shrimp. Live worms are an excellent food as worms are composed of a good supply of oil. Baby saltwater is best but hard to come by for land locked aquarists.
It is not our fishes fault if we can not supply the foods they need, it is our fault.
Paul b is offline   Reply With Quote
Old 04-05-2011, 09:57 AM   #5
Novel Responder
Join Date: Jul 2010
Location: Libertyville, IL
Posts: 4,371
Great post, as usual.
Just Stop!!!
richkor is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Is this Fish reef Safe? (Princess Parrot Fish) Deuter General Reef Discussion 13 01-30-2012 10:18 PM
types of fish for outdoor fish ponds ozzyoz TCMAS 5 04-19-2011 05:44 PM
Free fish to good home, 125 gallon tank and all equipment after fish gone. kristybe Atlanta Reef Club 2 08-02-2010 07:40 PM
Zeozym, Fish Immunstabil, Fish Amino Acids In Stock saltysupply Salty Supply 0 12-01-2008 08:23 PM
refugium & fish question (Free Fish to good home) trodder TCMAS 2 02-08-2004 12:07 AM

Similar Issues
Issue Issue Starter Forum Replies Last Post
pet supplies fish FISH FORUM ga serankko Atlanta Reef Club 68 2014-10-26 12:39:20
all the salt water fish tank supplies you will you for a 120 gallon fish tank for sale saltysupply Large Systems 69 2009-07-24 11:42:14
how do clown fish die die OR clown fish "" -finding -nemo -food -resteraunts BlackwaterMerk Reef Fish 8 2009-04-27 19:42:10
if a black and white clown fish pairs up with a orange clown fish what color will the babies be MissInk General Reef Discussion 6 2009-06-27 22:40:28

All times are GMT -5. The time now is 01:11 PM.

Powered by
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Our lawyer tells us that, by pressing the "New Thread" or "New Reply" button, you acknowledge that the opinions and information expressed in your article are yours alone and not those of thereeftank.com, dba The Reef Tank. Further, you agree to indemnify The Reef Tank, its moderators, administrators and agents from any and all liability which may arise as a result of your article. (C)opyright 2006 TheReefTank.com