Fat Fish In Hawaii

[csababubbles]

I just got back from a diving trip in Maui and almost every single fish I saw was as fat as can be, with huge bulging bellies. Moorish Idols, butterflys, angels, everything was huge and fat! Almost comical looking.

Lee, are we feeding enough in our aquariums? I get that there's a huge difference between the ocean and our tanks but why don't we want them eating like their wild counterparts in our tanks if our filtration can handle it?

Is it because there is such little room to swim that they don't need all those energy reserves? What am I missing here?

 

[greenmonkey51]

A lot of the fat stores could be preparation for spawning. Most fish I've seen in the wild weren't very fat. Most were well proportion or even a little thin.

 

[leebca]

Marine fishes are not 'fat in their bellies.'

Marine fishes store their energy reserves on the dorsal side. The 'top' of the fish is where the fat is stored. A full bellied fish just means it ate or is eating well -- not even necessarily the correct foods.

As you look straight on (face-to-face) to the fish, is the top half of the fish 'thick?' If so, that fish has stored its excess energy.

Many captive fishes come to us starved. A fine example is the Yellow Tang. Notice that you can see the lateral line of most YTs in the LFS? That is unnatural. A fish with properly stored energy in that area totally masks the lateral line so that it is invisible to the naked, untrained eye.

The reason why many of the fishes aren't like that in captive life is because we don't feed frequently enough nor (quite often) the correct foods. I just reviewed a feeding poll in another forum at another site. 40% feed their fishes once a day. That is slow starvation for most ornamental marine fishes.

In the wild these fishes constantly are feeding and eating the foods Nature intended (for the most part). This means they get the nutrients they need in the quantities they've evolved to process. Few hobbyists achieve this. Aquarists usually do achieve this. Professional aquarists almost always do achieve this.

 

[csababubbles]

yea i read on another site where all these people were posting they feed something like one cube of frozen food every day or two for several decently sized fish and were reasoning they would get the rest of their food from the live rock. i could hardly believe it!

could one extrapolate from your post that a captive fish is getting the proper nutrients it needs if the lateral line is masked and the top of the fish is thick? or can that also mean its just getting a lot to eat and not necessarily the correct nutrients?

also, will all fish have their lateral line masked if getting enough food and the right food or will it be evident on certain fish no matter how much they eat?

 

[leebca]

Not quite the correct extrapolation. Humans are a good example. Is a fat human getting the right nutrients? Not necessarily. A fat person can succumb to Rickets, Scurvy and other nutrient deficiency conditions.

A marine fish with an abundance of fat in its diet will tend to store this and appear 'healthy.' What's interesting about the wild fish is that they don't have much opportunity to obtain an abundance of fat -- their weight is put on vis a vis a more or less balanced diet. Necropsy will sometimes show the over-time effects of excessive fats and/or the wrong kinds of fats being fed to captive fishes.

I don't know offhand of any fish that would show its lateral line and yet have substantial energy reserves. There may be the odd one or two that are still ornamental marine fishes, that I haven't kept, or that I've not seen. Our fishes are, after all, laterally compressed, so I can imagine a particularly (naturally) thin/compressed fish might.

 

[csababubbles]

are there some particular foods that are key contributers to a fish getting too much "fat" in its diet? I read your feeding and nutrition posts quite a few times over the past year so I am well versed in what is good and what is bad for the fish but which is the source for the fat? is it the cheap fillers that have little nutritional value? I mean low grade does not necessarily mean it will lead to fatty liver, and other ailments associated with excess fats, does it? I hope you understand what I am trying to ask.

 

[leebca]

The hype driven home to aquarists is that they should be feeding their fishes HUFAs. So prepared foods often add more of these so they can claim on the package it contains HUFAs.

What few have done is determine what the correct 'balance' is when it comes to this and other ingredients. A lot of studies have been done on marine food fishes, but how that translates into the ornamental fishes group we don't know. We are assuming what applies to a sea bass applies to a Copperband Butterflyfish, and I'm not too sure we can make that leap.

Just-hatched brine shrimp, brine shrimp (decapsulated) eggs, cyclopeze, fat supplements, gut loaded brine shrimp with HUFAs, etc. are in a group with high levels of HUFAs. Some marine food fishes are also rich in this, which is one reason I avoid them in my feedings. If a homemade and/or prepared food contains a lot of these the shift is toward a high fat diet. Now, if the prepared food has too much HUFA in it AND the hobbyist soaks the food (as I recommend) in fat additives, alternating with vitamin additives, the shift moves even further toward a high fat diet.

In my homemade foods for instance, I choose one from the above group, but don't combine them. This kind of control isn't had in store-bought prepared foods. After all, if you're trying to sell a marine fish food product and the results are a fat fish, is that not a good product? It plays on the concept that a fat fish is a healthy fish, thus the food must be right. Hobbyists seem to have a double standard when it comes to fishes. A fat fish is good; a fat human is not good.

Quite often the 'cheap fillers' (if I understand you correctly) are not this culprit. Those fillers (like wheat) cause other problems or end up being worthless to the fish's system.

Not so much a 'grade' issue when it comes to fats in marine fish foods -- it's the wrong kinds of fats that cause internal problems. Most notable are the insides of a Lionfish that has suddenly died. When fed on a diet of freshwater fishes and freshwater foods, the fish develops distinct internal fat deposits of the non-HUFA kinds of fats. Yet hobbyists always find an excuse to get around this fact when it comes to their Lionfish and other predatory marine fishes -- "The fish loves to stalk and catch its (freshwater fish living) prey." Or the favorite of mine: "It's a treat." Yeah. Like I would give my children arsenic as a treat.


As usual, if I've misread or misunderstood your questions/points, just let me know.

 

[csababubbles]

that was perfect. thanks so much for your explanations!