Brown Tang

[koopa]

he's already died because I made a mistake of putting him in 20 gal tank. But i wanted to know why his eyes were like that (which caused him to not see) and why it killed off the other fishes days after. Is it marine ich or velvet?

[leebca]

It's a severe case of Marine Ich on an emaciated fish. Undernourished and weak, the disease just took the fish over. The parasite attacks all surfaces.

The cloudy eyes is usually from a secondary bacterial infection which often follows the parasite invasion.

[koopa]

It's a severe case of Marine Ich on an emaciated fish. Undernourished and weak, the disease just took the fish over. The parasite attacks all surfaces.

The cloudy eyes is usually from a secondary bacterial infection which often follows the parasite invasion.

Ok thanks. FYI though, he wasn't undernourished or emaciated...he was well-fed and eating everything and things turned bad within the space of 1-2 days at night.

[Parrothead]

Quite possibly caused by adding too many fish to a tank all at once that hadn't even completed it's int. nitrogen cycle

[leebca]

The lateral line on this fish should not be visible. Fat/energy is stored on the dorsal side of the fish and this line being so prominently visible indicates the fish was emaciated. Why it was emaciated, I don't know. It could be the wrong kinds of foods, the wrong quantity of foods, etc.

[berkdog]

The lateral line on this fish should not be visible. Fat/energy is stored on the dorsal side of the fish and this line being so prominently visible indicates the fish was emaciated. Why it was emaciated, I don't know. It could be the wrong kinds of foods, the wrong quantity of foods, etc.

Lee, if you're able to see the skeleton of a fish, does it mean they are starving or something? I see this sometimes in similar fish to the brown tang in my local fish store, and I always think they need to be fed more, but the fish store employee says that it changes colors and when it is lighter, it's easier to see their skeleton. I noticed it while there, but I wonder if they're starving too.

[koopa]

The lateral line on this fish should not be visible. Fat/energy is stored on the dorsal side of the fish and this line being so prominently visible indicates the fish was emaciated. Why it was emaciated, I don't know. It could be the wrong kinds of foods, the wrong quantity of foods, etc.

Well the skin looked dry. I fed it marine 1 pellets and mysis and it ate well when it was doing fine. IT also ate a lot of algae on the liverock and sand. Apart from the skin it didnt look underfed to me.

[leebca]

berkdog,

One way to tell if the fish has been getting enough food is to find out if it has stored energy. Fat is their energy storage. The fat of a laterally compressed ornamental fish is stored on the dorsal side. Don't evaluate a fish based on the size or shape of it's digestive/stomach area. And there are such things as an overweight captive fish! Just, you won't find them in hobbyist's tanks.

Now, just because the fish has stored fat doesn't in of itself mean the fish has been fed properly. It just means the fish has managed to gather enough extra energy. So 'fatness' is not a sign that fish was fed properly. You use other clues to determine this: behavior, color, attitude, alertness, etc. On the other hand, seeing the Lateral Line (LL) is an indication the fish is not thriving.

A fish without enough stored energy to hide it LL is a fish not getting enough to thrive. It's the difference between surviving and thriving: Survive or Thrive?

In a Tang, the LL runs right along where the fat is stored. A fish with fat stored there in sufficient quantity to handle a major stressor doesn't exhibit its Lateral Line. If the fish is so thin that you can see it, then the fish shouldn't be this thin.

In the case of Yellow Tangs, they often have a 'skin marking' of a whitish line along their LL. When they darken, the marking shows up prominently. When they fade, it's harder to tell. Don't confuse marking with its LL. You need to be able to tell the difference of the marking from the LL.

The problem with Tang husbandry is that most hobbyist don't know how to do it. The Tang in the wild travels miles every day, over long distances, to constantly browse on algae. In captivity that same food source must be met through a long part of the day. Thus I wrote how to feed macro algae to fishes and how much to feed them in this post: How To Feed Macro Alage to Marine Fishes

As the fish gets older it turns more and more towards being a herbivore. The very young ones are almost omnivores (out of necessity I believe -- they can't travel to eat enough algae without getting killed!). The 4" Tang is pretty much a herbivore. It needs a lot of greens in its diet, fed three plus times each day. The prepared foods it's offered should contain a high content of algae, spirulina, with a lesser amount of fish proteins. Also, it should be noted as an aside, herbivore fishes, like Tangs, are heavy tank polluters.

So those you see in the store:
They have been starved since they were captured. Most arrive through the system to the LFS starved. They don't get fed enough there even, but ideally, at the LFS they will be trained to eat in captivity and start eating the right foods. Anyway, these fish are what you are seeing and, to some extent, thinking they are 'normal.'

In some Asian countries, Tangs are a food fish -- they are so fat and juicy! I can't imagine eating one of those I see in the LFS tanks -- no 'meat' on them.

Just remember, it's not the whole skeleton -- its the Lateral Line of the fish that should not be exposed. They can have a 'fat belly' but be mal nourished.

Hope this helps better understand.