Estimating fish sizes in captivity
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Aquarist007
New member
<a href=showthread.php?s=&postid=14940482#post14940482 target=_blank>Originally posted</a> by jenglish
This is RC, threads wander off topic constantly
IMO it hasn't really wandered off topic much--its still related to fish health and the "unhealthy" signs they might show if kept in too small a tank.
Paul B
Premium Member
NexDog I forgot about Bangai Cardinals, I have to step on mine to stop them from spawning. I bet if you eliminated the frozen food they wouold stop spawning. Anyway if they are spawning they are very healthy. Spawning behaviour is not a short term health sign. A fish needs a constant state of good health to keep developing eggs. They will expell or re absorb eggs if their diet is not adaquate or if envirnmental conditions change and as soon as they spawn, they start developing more eggs.
Fish spawning with ich is a hard subject to approach as fish handle ich differently depending on their health. There is always ich in my tank. I have not quaranteened in decades, I use NSW straight from the sea along with rocks, seaweed, worms amphipods, crabs snails etc. so I am quite sure it is in there. If a fish in my tank is near death from old age it will show signs of ich and eventually that is what will end it's life but it will only show when the fish is on it's last few days.
The paracite is on all wild fish at some time and fish in breeding condition have no problem with it.
Ich is a natural part of the sea, fish have paracites just as humans do. We are covered in them, some of us more than others but they are there happily eating our dead skin cells.
They don't enter our skin because we have defenses for that just as fish do, healthy fish.
People sometimes do not understand that fish are not humans, they have different stages of health than we do. It is a different animal. They can lose a fin and re grow it very quickly, we don't grow limbs. They can appear healthy and live a long time but not be able to breed because of lack of nutrients. As I said, people can breed even if they are almost dead.
We can fight off disease even if we sit around, drink beer and eat hot dogs all day. fish can not. Their health is directly proportional to their diet. A healhty looking fish is not always a healthy fish.
I have a hippo tang in marginal health. He will probably live another 10 years but even if this fish was in the sea, he would never be able to spawn. He has some form of either autoimmune disease (if that is even possable in a fish) or a cancer. He got it from an envirnment condition a few years ago and never fully recovered.
OK lets start talking about Paris Hilton
Fish spawning with ich is a hard subject to approach as fish handle ich differently depending on their health. There is always ich in my tank. I have not quaranteened in decades, I use NSW straight from the sea along with rocks, seaweed, worms amphipods, crabs snails etc. so I am quite sure it is in there. If a fish in my tank is near death from old age it will show signs of ich and eventually that is what will end it's life but it will only show when the fish is on it's last few days.
The paracite is on all wild fish at some time and fish in breeding condition have no problem with it.
Ich is a natural part of the sea, fish have paracites just as humans do. We are covered in them, some of us more than others but they are there happily eating our dead skin cells.
They don't enter our skin because we have defenses for that just as fish do, healthy fish.
People sometimes do not understand that fish are not humans, they have different stages of health than we do. It is a different animal. They can lose a fin and re grow it very quickly, we don't grow limbs. They can appear healthy and live a long time but not be able to breed because of lack of nutrients. As I said, people can breed even if they are almost dead.
We can fight off disease even if we sit around, drink beer and eat hot dogs all day. fish can not. Their health is directly proportional to their diet. A healhty looking fish is not always a healthy fish.
I have a hippo tang in marginal health. He will probably live another 10 years but even if this fish was in the sea, he would never be able to spawn. He has some form of either autoimmune disease (if that is even possable in a fish) or a cancer. He got it from an envirnment condition a few years ago and never fully recovered.
OK lets start talking about Paris Hilton
Aurora D.
New member
<a href=showthread.php?s=&postid=14941576#post14941576 target=_blank>Originally posted</a> by Paul B
NexDog I forgot about Bangai Cardinals, I have to step on mine to stop them from spawning. I bet if you eliminated the frozen food they wouold stop spawning. Anyway if they are spawning they are very healthy. Spawning behaviour is not a short term health sign. A fish needs a constant state of good health to keep developing eggs. They will expell or re absorb eggs if their diet is not adaquate or if envirnmental conditions change and as soon as they spawn, they start developing more eggs.
Fish spawning with ich is a hard subject to approach as fish handle ich differently depending on their health. There is always ich in my tank. I have not quaranteened in decades, I use NSW straight from the sea along with rocks, seaweed, worms amphipods, crabs snails etc. so I am quite sure it is in there. If a fish in my tank is near death from old age it will show signs of ich and eventually that is what will end it's life but it will only show when the fish is on it's last few days.
The paracite is on all wild fish at some time and fish in breeding condition have no problem with it.
Ich is a natural part of the sea, fish have paracites just as humans do. We are covered in them, some of us more than others but they are there happily eating our dead skin cells.
They don't enter our skin because we have defenses for that just as fish do, healthy fish.
People sometimes do not understand that fish are not humans, they have different stages of health than we do. It is a different animal. They can lose a fin and re grow it very quickly, we don't grow limbs. They can appear healthy and live a long time but not be able to breed because of lack of nutrients. As I said, people can breed even if they are almost dead.
We can fight off disease even if we sit around, drink beer and eat hot dogs all day. fish can not. Their health is directly proportional to their diet. A healhty looking fish is not always a healthy fish.
I have a hippo tang in marginal health. He will probably live another 10 years but even if this fish was in the sea, he would never be able to spawn. He has some form of either autoimmune disease (if that is even possable in a fish) or a cancer. He got it from an envirnment condition a few years ago and never fully recovered.
OK lets start talking about Paris Hilton
I think that could be summed up as fish and humans evolved in different conditions, thus they can't really be compared to us or any other mammal for that matter.
Aquarist007
New member
<a href=showthread.php?s=&postid=14941576#post14941576 target=_blank>Originally posted</a> by Paul B
OK lets start talking about Paris Hilton
She looks very healthy to me-----is ich going to take over her body when she is old?
Is her health due to living in a giant environment or a great diet?:lol:
Does she eat only live food and no flake
And does she spawn regularily:eek2
...and finally is her height only 66 percent of what it should be:lol:
Paul B
Premium Member
Jeremy, everything I say is an assumption. No one here is the God of fish, well maybe Waterkeeper, but all the rest of us mortals just have assumptions.
My assumptions have evolved and changed many times over the years. Every time I dive I learn something different.
I am a very observant diver and not a resort diver (although I have dove with a lot of resorts)
You really need to swim with fish and spend a lot of time with them intensely observing how they make their living before you can come up with an "assumption" as to what they are supposed to look like then we can compare the differences we see in captive life. Captive fish look and act vastly different in the sea then in our tanks.
At one time or another I have had all size tanks from one gallon to 100 gallons, I even kept them in wine barrels. I know from experience that most, but not all fish will be stunted in a tank.
Panther groupers get three feet long, in a tank they can live quite well and grow to about a foot. Still to large for most tanks and I don't advocate keeping those fish.
I have seen green Morays almost 12 feet long. One of them almost took off the arm of a jerk I was diving with.
I personally don't think a slightly stunted fish is in too bad a shape as to health. I don't think anyone can make that determination byt, yes, it would be much better to keep them in the largest tank possable.
I would also like a larger home, maybe that is why I am not 6' tall.
I still can spawn though
Aquarist007
New member
<a href=showthread.php?s=&postid=14941940#post14941940 target=_blank>Originally posted</a> by Paul B
Jeremy, everything I say is an assumption. No one here is the God of fish, well maybe Waterkeeper, but all the rest of us mortals just have assumptions.
My assumptions have evolved and changed many times over the years. Every time I dive I learn something different.
I am a very observant diver and not a resort diver (although I have dove with a lot of resorts)
You really need to swim with fish and spend a lot of time with them intensely observing how they make their living before you can come up with an "assumption" as to what they are supposed to look like then we can compare the differences we see in captive life. Captive fish look and act vastly different in the sea then in our tanks.
At one time or another I have had all size tanks from one gallon to 100 gallons, I even kept them in wine barrels. I know from experience that most, but not all fish will be stunted in a tank.
Panther groupers get three feet long, in a tank they can live quite well and grow to about a foot. Still to large for most tanks and I don't advocate keeping those fish.
I have seen green Morays almost 12 feet long. One of them almost took off the arm of a jerk I was diving with.
I personally don't think a slightly stunted fish is in too bad a shape as to health. I don't think anyone can make that determination byt, yes, it would be much better to keep them in the largest tank possable.
I would also like a larger home, maybe that is why I am not 6' tall.
I still can spawn though
Paul---have you ever compared the longevity of your "stunted" fish to their much bigger species in the wild or there studies where this has been done.
As far as you still spawning--first of all that is too much infomation but secondly I don't doubt it with the amount of oysters you consume:lol:
Paul B
Premium Member
Capn the oysters do it.
I have no way to find out the lifespan of a fish in the sea but I am old enough to have had fish live up to 18 years in my tank.
One of my percula clowns was 12 and was kept in a 40 gallon tank. He stayed about 2",much smaller than a similar fish in the sea.
As I said my hippo tangs never get larger than about 5" or so in my 100 gallon and my 5 year old moorish Idol grew to about 6" which is about 2" smaller than they get in the sea.
Those fish seemed to live long healthy lives but none of those particular fish ever spawned. I never had them paired with anything so I don't know if they could have spawned.
I did keep blue devels in a 30 gallon tank for about 12 years, they also were smaller than their wild counterparts but they spawned continousely for years.
Here he is over his nest of eggs circa 1973
I have no way to find out the lifespan of a fish in the sea but I am old enough to have had fish live up to 18 years in my tank.
One of my percula clowns was 12 and was kept in a 40 gallon tank. He stayed about 2",much smaller than a similar fish in the sea.
As I said my hippo tangs never get larger than about 5" or so in my 100 gallon and my 5 year old moorish Idol grew to about 6" which is about 2" smaller than they get in the sea.
Those fish seemed to live long healthy lives but none of those particular fish ever spawned. I never had them paired with anything so I don't know if they could have spawned.
I did keep blue devels in a 30 gallon tank for about 12 years, they also were smaller than their wild counterparts but they spawned continousely for years.
Here he is over his nest of eggs circa 1973
LobsterOfJustice
Recovering Detritophobe
Regarding the spawning...
This kind of goes with pauls last post as well...
Even assuming breeding is a indicator of health (which obviously is debatable since we're currently arguing about that), we only see smaller fish breeding in our tanks. The banggai's gobies, and clowns that often breed in our tanks are all small fish, that are more apropriate for home aquariums and therefore not effected by the stunting etc.
The equivalent of putting an average larger tang, rabbit, angel etc in a 4' tank (at their average sales sizes of 4"-5") is roughly like putting a juvenile clown (3/4", ~2 mos old) in a 2.5 gallon tank. Despite the widespread success of breeding clowns in home aquariums, I am sure a small pair of clowns, placed in this tank, would not breed.
The only reports I've heard of tangs breeding in home aquariums are in atlantis marine world's 20,000 gallon tank.
So I'm not really sure why we're arguing about the semantics of wether breeding indicates health, because the fish in question ARENT breeding in our tanks, so it doesnt really matter, right?
This kind of goes with pauls last post as well...
Even assuming breeding is a indicator of health (which obviously is debatable since we're currently arguing about that), we only see smaller fish breeding in our tanks. The banggai's gobies, and clowns that often breed in our tanks are all small fish, that are more apropriate for home aquariums and therefore not effected by the stunting etc.
The equivalent of putting an average larger tang, rabbit, angel etc in a 4' tank (at their average sales sizes of 4"-5") is roughly like putting a juvenile clown (3/4", ~2 mos old) in a 2.5 gallon tank. Despite the widespread success of breeding clowns in home aquariums, I am sure a small pair of clowns, placed in this tank, would not breed.
The only reports I've heard of tangs breeding in home aquariums are in atlantis marine world's 20,000 gallon tank.
So I'm not really sure why we're arguing about the semantics of wether breeding indicates health, because the fish in question ARENT breeding in our tanks, so it doesnt really matter, right?
Paul B
Premium Member
Lobster, that is true but unfortunately, for our purposes only small fish which are commonly available to us are the types of fish that lay eggs in a nest. Tangs and angels are egg scatters and I doubt they will even attempt to spawn unless they are in a school in a large quantity of water.
You could probably get a flounder to spawn in a tank but the fish is almost a foot long when it is mature so we really can't try with that fish.
So I guess we will just have to go aimlessly about our business and we will never know.
One of the things about captive fish is we, as their caretakers, only feed them to our own preferences. In real life fish feed most of the day.
Aquarist007
New member
Water Keeper--glad you joined in--I guess being Sunday afternoon they let you out of the new to the reef forum
Are you saying that is a stressor that contributes to less of a life span in captivity and to dwarfism in captive fish?
It makes alot of sense if you extrapolate that to a very large tang--it would be impossible to provide grazing all day in our tanks.
So how do they do it in huge public aquariums that have hundreds of tangs?
greenmonkey51
New member
This study is a joke. The fact that it was reported is an embarrassment to real studies. Besides grouping together salt and freshwater fish he didn't even use fish that were anywhere close to being related. The fact that he came to this conclusion with 19 samples is the biggest farce.
jenglish
Marquis de Carabas
This was more of an exploratory study that the author talked about on what appears to be more of a blog than it being published. I don't think it was meant to be ready for a peer reviewed science journal. It is hard to make some general conclusions with n=19, but I think one can talk about it descriptively.
Paul B
Premium Member
Capn, last week I took the backstage tour of the Monteray aquarium in California. There they only use NSW and it is not even filtered for the most part. There is a lot of algae growing on the rocks and the fish can eat all day.
Also, they don't keep the local fish indefinately, after a period of time, they release them back to the sea and aquire new specimins so the fish don't get a chance to be mal nourished or stunted.
The tangs are not released but are also in NSW tanks where there is abundant algae and they are also fed krill a few times a day. Heavy feeding is possable due to the large volume of water that is completely re newed every two and a half hours.
Paul B
Premium Member
I disagree, Jay is a respected aquarist and his limited study makes perfect sense to me. It is a place to start and it proves
(not scientifically) how fish are stunted. Many people do not even believe the size of a tank will stunt fish. Those people have not kept fish long.
Any knowledge we gain is helpful.
