Do tangs really need at least 180 or larger in most cases?

Slocke

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That's also a little bit of confirmation bias. The big fat giant tangs you see in the wild are the exception, not the norm - they spawn in the thousands and very few survive to that age. Of those that do, not all of them will ever reach that size even in the wild. Size variation in our own species is as high as 4x between healthy individuals. We wouldn't claim someone is malnourished because they aren't Hafþór Julius Bjornsson. That 'max size' is just that. It's like listing the max height of a human at 7'6" because Yao Ming exists. It should be a bell curve. Like a yellow tang can get to 8 inches long but on average the peak of the bell curve is more like 6 inches.
I'm saying the average weight of a wild tang compared to a captive is a lot higher then when compared to other fish. Which means that either the lack of space or the diet is having a greater effect on the health than it is other fish. Now predation is a vital part of keeping a population healthy and while that may explain why captive species are more likely to be unhealthy it does not explain why our tangs living the easy life fail to reach the health of wild species.

I oppose this to groups of other fish like damsels and wrasse which from my observations are often much fatter in captivity than in the wild.
But I'm sure diet helps too. They are definitely getting what they need from a meat-rich diet but perhaps with a primarily veggie diet they grow slower but also grow for much longer?
Predominantly herbivorous animals can develop issues from eating a protein based diet. It depends on their digestive system and I'm no fish expert but symptoms can range from constipation and/or diarrhea to blood being poisoned with high levels of ammonia or urea. From looking at threads on here it seems to cause constipation and lack of appetite sometimes leading to starvation in tangs and rabbitfish.
 

Slocke

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This is the part I'm questioning. Do we have evidence that this is actually the case?
I can’t answer that. Just my observation. I was shocked how fat wild tangs were when I went on several dives for the first time in years.

But how many tanks have enough algae to allow a tang to almost constantly graze on algae like they do in the wild? I’m not saying nibble on tiny scraps around the tank but actually enough algae to get a good and consistent meal?
 

ninjamyst

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I have three big tangs in my 6 ft 200g tank. You may think they just hang out in one spot because when they see people, they go where food is normally dropped. If you ever set up a camera and watch what they do all day, 90% of the time they are swimming everywhere and grazing. They love swimming in and out of ledges, caves, etc. They love riding the currents.
 

blecki

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We need to know percentages. How many of all of a species were that size? Then we can compare to the hobby, where we also need to know percentages. The data doesn't exist to determine if there even is a disparity in max size and we haven't even gotten to the stage of adjusting for mortality.
 

exnisstech

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I keep a purple, yellow, hippo, convict, and Naso in a 6x2x2ft 180. They are all fat and healthy and I have zero aggression. They all get along so well I no longer add any other fish as I'm afraid of disrupting the harmony I seem to have in the tank. They use the whole tank but they just cruise around and don't swim/pace back and forth like I have seen some fish do. I don't know if it's true or not but when I see a fish swimming back and forth over and over I feel like they are nervous or just not comfortable in their surrounding. I bought all but the yellow as juveniles going back over 7 years for some.
I also keep a yellow and a two spot bristletooth in a 36x24x24" tank. They just cruise around grazing on the rocks and do not appear stressed at all. The yellow wasn't meant for the smaller tank but it most likely would have been killed in the 180 as the other yellow was attacking it non stop even biting it's fins in addition to tail smacking.
 

ninjamyst

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I keep a purple, yellow, hippo, convict, and Naso in a 6x2x2ft 180. They are all fat and healthy and I have zero aggression. They all get along so well I no longer add any other fish as I'm afraid of disrupting the harmony I seem to have in the tank. They use the whole tank but they just cruise around and don't swim/pace back and forth like I have seen some fish do. I don't know if it's true or not but when I see a fish swimming back and forth over and over I feel like they are nervous or just not comfortable in their surrounding. I bought all but the yellow as juveniles going back over 7 years for some.
I also keep a yellow and a two spot bristletooth in a 36x24x24" tank. They just cruise around grazing on the rocks and do not appear stressed at all. The yellow wasn't meant for the smaller tank but it most likely would have been killed in the 180 as the other yellow was attacking it non stop even biting it's fins in addition to tail smacking.
There's just something amazing watching tangs swim and interact with each other. My two yellows and a purple love to bicker and "dance". At first I thought they are fighting but now I know they just playing.
 

exnisstech

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There's just something amazing watching tangs swim and interact with each other. My two yellows and a purple love to bicker and "dance". At first I thought they are fighting but now I know they just playing.

I was surprised that I had to seperate my two yellows. I thought the purple would be the problem and moved it to time out for a week when I added the yellows. They were in QT together with an eggcrate divider and didn't really even pay attention to each other. A week after placing them in the 180 one went after the other non stop. The one would not even fight back so I knew I had to intervene. The purple has turned out to be the most docile of them all.
 

jda

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Chocolate tang is among the best for small tanks, IMO. This fish just kinda cruises slowly and picks and does not dart and dash and stuff.

Tangs are omnivores. They need meat or else they will live short lives and die, IME. The algae that they dine on in nature is covered with zooplankton that give them fatty acids, vitamin E, etc. If you just try and feed your tanks nori, they will suffer. Many omnivores eat more of one kind of food than another, but I wish that nobody would call tanks herbivores since it is wholesale inaccurate. Balance with a lean to plants is probably best. Pellets with spirulina as one of the first ingredients are a good place to start for a staple. BTW - triggers are omnivores too... I have had triggers that would eat whole sheets of nori.

I have yellow and purple tang older than one of my kids who is in college. 7 and 8 foot tanks here. They are big and fat with no diseases or HLLE marks or anything, but still not as big as you see in the ocean in Hawaii. I don't feel bad. I doubt that they would have gotten this old in Hawaii or the Red Sea, but there is a very small chance.
 

CBonito

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the 90 dollar purple tangs on Black Friday were killing me inside because i only have a 20 gallon lol
That's about the only tang I would go for anymore, but even they can be neurotic.
If they get claustrophobic, they're going to be aggressive and until the fish dies, it's going to be a problem for itself and other fish.

I'm avoiding them altogether anymore. My tank is more than twice the size of that and I wouldn't do it.
 

Paul B

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These guys live fine in my 125 gallon tank and even after 10 years they are very healthy but don't outgrow the tank.



Before this tank I kept them for the same amount of years in a 100 gallon tank and before that I kept one in a 40 gallon tank for 5 years. They just seem to stop growing in a smaller tank but I feel 100 gallons is about the smallest they should be put in.
 

CBonito

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These guys live fine in my 125 gallon tank and even after 10 years they are very healthy but don't outgrow the tank.



Before this tank I kept them for the same amount of years in a 100 gallon tank and before that I kept one in a 40 gallon tank for 5 years. They just seem to stop growing in a smaller tank but I feel 100 gallons is about the smallest they should be put in.
I've always gotten mixed info on that, whether they will outgrow their tank or not. And I've seen some do and some don't. It's hard to know which though. The problems I've always had were relevant to "pecking order" and not room.
 

braaap

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My Kole and Yellow were happy for 3 years in essentially a 40B. Constantly swimming. Ate like pigs. Lots of hiding spots. Sold them when I had to move and shut down.

That said I would have rehomed them before 5 years due to their potential size.
 

blecki

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The algae that they dine on in nature is covered with zooplankton that give them fatty acids, vitamin E, etc.
My issue is always keeping the tangs from filling up on the 'good stuff' the other fish are getting so that they actually eat the nori.
 

Frenchy

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My issue is always keeping the tangs from filling up on the 'good stuff' the other fish are getting so that they actually eat the nori.
I keep 3 large tangs (purple, power blue and hippo) in a 7ft long shallow 12x18 reef. They all grew up together, get along fabulously and appear to love the long runway. They are a joy to watch. Wouldn’t dare put another in there now.
 

Leadfooted

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I don’t read the news so I didn’t get the memo. . 90 gallons , happy family.

IMG_4009.jpeg
 

exnisstech

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I've always gotten mixed info on that, whether they will outgrow their tank or not.
Same. I do think tank mates have an effect on growth. I believe it's a dominance thing. No scientific data but I had a nice size yellow tang maybe 4 or 5 inches or so. I introduced a purple that was quite a bit smaller than the yellow but the purple became dominant and the yellow just stopped growing and the purple ended up considerably larger than the yellow. I know purples tend to grow larger than yellows but it's like the yellow one just stopped growing after the addition of the purple. This was in a 6ft 150g.
 
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Frenchy

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I keep 3 large tangs (purple, power blue and hippo) in a 7ft long shallow 12x18 reef. They all grew up together, get along fabulously and appear to love the long runway. They are a joy to watch. Wouldn’t dare put another in there now.
System water volume with the sump is only about 75 gal. Weekly water changes are a must. So my answer is you don’t need a huge tank, just a lot of swimming room if you want them to thrive.
 

merkmerk73

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The simple answer is no

The complicated answers is it depends on tank shape

A long tank gives tangs the space they need to cruise


A 5ft tank is more than enough for most tangs - but not all tangs

Anyone that tells you otherwise is probably also going to tell you bettas need 5g tanks minimum and that cow farts are going to destroy the planet
 

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