Comet mouth question

[ichthyogeek]

How big of a fish can comets eat? I've read that they'll go after baby mollies, but I've also seen the same in Banggai cardinalfish, only for the BC to stop eating them after they gain some heft. So how big of a fish can comets eat?

@ThRoewer ?

 

[lion king]

They will eat fish about 1/3 of their size, body size not including fins. These fish are all fins, so look at their body. They will not eat rotund fish but slender fish are easy game. My 5-6" comet ate mollies over an inch with glee. They are groupers, so same rules apply, just on a smaller scale.

 

[ThRoewer]

How big of a fish can comets eat? I've read that they'll go after baby mollies, but I've also seen the same in Banggai cardinalfish, only for the BC to stop eating them after they gain some heft. So how big of a fish can comets eat?

@ThRoewer ?

They don't eat fish unless you let them starve to a point of desperation.
I actually tried feeding them frozen fish and they would just ignore it or turn away as if I offended them.
All they normally eat are crustaceans, shrimp and pods.

 

[ThRoewer]

They will eat fish about 1/3 of their size, body size not including fins. These fish are all fins, so look at their body. They will not eat rotund fish but slender fish are easy game. My 5-6" comet ate mollies over an inch with glee. They are groupers, so same rules apply, just on a smaller scale.

First of all, they are not groupers, not even related.
Second, you would have had trained that fish to eat other fish. By default they don't even look at fish as food source.

 

[lion king]

First of all, they are not groupers, not even related.
Second, you would have had trained that fish to eat other fish. By default they don't even look at fish as food source.

Sorry I had a comet live years with lions and a ribbon eel, he ate live guppies and mollies with the rest of them. As adults they were fed mollies that were over an inch. The comet is a very capable predator, just recently a member posted a vid of his hunting and eating guppies. They are also know as the marine betta grouper and the comet grouper, so if not a grouper or related to a grouper; their family tree does include groupers.

 

[ThRoewer]

Sorry I had a comet live years with lions and a ribbon eel, he ate live guppies and mollies with the rest of them. As adults they were fed mollies that were over an inch. The comet is a very capable predator, just recently a member posted a vid of his hunting and eating guppies. They are also know as the marine betta grouper and the comet grouper, so if not a grouper or related to a grouper; their family tree does include groupers.

Their family tree is extremely far from groupers. Just because uninformed people call them groupers doesn't make it a fact. "Mandarin gobies" also have no closer relationship to gobies other than that both are teleosts.
In fact, the marine betta and fellow roundheads are closer related to Blennies and basslets.
I have and have had many pairs of Calloplesiops over the years, over 20 individuals, and had them with small fish they could have easily eaten, yet none of them ever even looked funny at another fish.
Of course, if you keep them in a predator tank and primarily feed live fish they will do what everyone else there does. But that counts as conditioning or training. Normally fish are not on their menu.

 

[lion king]

Their family tree is extremely far from groupers. Just because uninformed people call them groupers doesn't make it a fact. "Mandarin gobies" also have no closer relationship to gobies other than that both are teleosts.
In fact, the marine betta and fellow roundheads are closer related to Blennies and basslets.
I have and have had many pairs of Calloplesiops over the years, over 20 individuals, and had them with small fish they could have easily eaten, yet none of them ever even looked funny at another fish.
Of course, if you keep them in a predator tank and primarily feed live fish they will do what everyone else there does. But that counts as conditioning or training. Normally fish are not on their menu.

It's actually opposite, you train them to eat dead food, what do you think they eat in the wild. Their main diet is crustaceans and small fish, live; not served on a platter like in "a pineapple under the sea". They are so much more fantastic when they eat live, more active and bold, and put on such a show.

If you get a small one and grow them up on dead food, they'll likely leave your fish alone. But if you get a mature one direct from the ocean and put them inwith your small fish, oh well, you know what;s going to happen. Many times these guys actually need live food to settle them into captivity.

 

[ThRoewer]

It's actually opposite, you train them to eat dead food, what do you think they eat in the wild. Their main diet is crustaceans and small fish, live; not served on a platter like in "a pineapple under the sea". They are so much more fantastic when they eat live, more active and bold, and put on such a show.

If you get a small one and grow them up on dead food, they'll likely leave your fish alone. But if you get a mature one direct from the ocean and put them inwith your small fish, oh well, you know what;s going to happen. Many times these guys actually need live food to settle them into captivity.

In the past, I only bought extra large ones as broodstock and fed their tanks live shrimp and gobies I collected on the Northsea coast. My Amphiprion clarkii would eat the gobies and even my ocellaris gave them a shot but the Marine Betta would only hunt the shrimp and not even take dead gobies I held with tweezers right in front of them.
I also quarantined newly acquired Marine Betta with smaller fish they could have easily eaten but they didn't. The gobies I quarantined with my Tiger Jawfish were not so lucky...

 

[mort]

I'm somewhere in the middle with my views. Do they have the potential to eat fish, yes but ime they don't normally eat them.
The only fish you normally have to worry about are very small and slender species like trimma, canna gobies etc.

I had a clownfish grow out tank connected to my betta tank and four babies, about an inch, jumped into the display with my, nearly 8" betta. I removed the clowns when they were a couple of inches long but they lived with the betta without issue for months. My cleaner shrimps on the other hand became dinner when the betta grew to be just slightly larger than them. I thought I had plenty of time but it must have got them after moulting. So I'm more worried about inverts than fish, assuming your sensible with the fish you choose.

 

[OrionN]

I don't breed Marine Betta but keep pairs of them for many year. Thomas, AKA @ThRoewer, does extensive literature researches on fishes that he breed (?and other subjects). He knows about Marine Betta and he was published pioneer in breeding Marine Betta breeder from way back.
FWIW, I never have problem with my Marine Betta eating fish, only inverts. I never target feed them at all and they always fat and healthy. Like Thomas, I do keep them in a more natural setting which is in a large reef 420 or 320 gal with a lot of live rocks and full of fauna. They hunt and eat in the rock. Occasionally they eat a frozen mysis or two, but never very much becasue they are slow and deliberate. By the time they eat one or two, the mysis are all gone.

 

[lion king]

Most fish are natural predators, we are the ones that change their nature by feeding them dead food. I have always kept bettas in my predator tanks, as well as others that I know, you'll even find members here if you visit the Predator forum. It's very common that newly acquired wild individuals need to fed live food. The captive bred ones usually don't acquire their original nature but I know people that have lost small fish to newly acquired wild ones. Another fish some of you would likely dispute is the hawkfish, I keep a flame hawkfish in one of my predator tanks, he also eats live guppies. I think the original question was "how big a fish can a comet eat", they will eat fish but they can also live peacefully with fish.

 

[vetteguy53081]

When I had my pet store, I often told customers to consider this when thinking about adding something new to their tank:
ANY FISH THAT CAN FIT IN THE MOUTH OF ANOTHER FISH, sooner or later Will !! )

 

[OrionN]

When I had my pet store, I often told customers to consider this when thinking about adding something new to their tank:
ANY FISH THAT CAN FIT IN THE MOUTH OF ANOTHER FISH, sooner or later Will !! )

I think it depends on how much we feed them. My Harlequin Tusk never eat any fish. I just need to be careful when I add a small fish. My HT is lazy and rather eat out of my hand rather than hunt fish or shrimp for food.

 

[ThRoewer]

The thing is that you can train a fish to eat something it would not eat in the wild but you cannot untrain it to go after its natural prey. A hungry lionfish will always eat any smaller fish he can swallow.
The fact that none of my (MANY) Marine Bettas ever ate a fish - not even tiny clumsy clownfish babies that were swimming right next to them, not even if I had not fed them for a few days - tells me that fish isn't on their natural meal plan. In fact, they primarily go after small crustacean, like Mysids, Amphipods, and Copepods. They go without hesitation after Tigriopus from day one without any training. No freshly imported Lionfish would even look at such tiny food.

 

[lion king]

The thing is that you can train a fish to eat something it would not eat in the wild but you cannot untrain it to go after its natural prey. A hungry lionfish will always eat any smaller fish he can swallow.
The fact that none of my (MANY) Marine Bettas ever ate a fish - not even tiny clumsy clownfish babies that were swimming right next to them, not even if I had not fed them for a few days - tells me that fish isn't on their natural meal plan. In fact, they primarily go after small crustacean, like Mysids, Amphipods, and Copepods. They go without hesitation after Tigriopus from day one without any training. No freshly imported Lionfish would even look at such tiny food.

Many sources do list the natural diet of the comet as crustaceans and small fish. It is pretty common that wild caught specimens will not eat until 1st being acclimated by live food which will include ghost shrimp, guppies, and small mollies. Wild caught individuals have a dismal survival rate mainly due to feeding difficulties as well as the prevalence of internal parasites. You may hear one success story here or there but I know of dozens that never lived more than a few months.

 

[OrionN]

I never have one that fail to live for years. All mine were wild caught. My next three in two tanks will be tank raise by @ThRoewer

 

[lion king]

I never have one that fail to live for years. All mine were wild caught. My next three in two tanks will be tank raise by @ThRoewer

You sir are an exception to the rule, you handle many difficult individuals that many can not. Just as I have a high success with lions, most do not. We have to consider overall success not just our own, most people have a very hard time with wild caught comets.

 

[ThRoewer]

Many online sites and books state a lot of things that are not correct or poorly researched. I would want to see stomach content analysis of wild specimens to be convinced that fish are part of their natural diet.

As for the dying quickly, that may have more to do with cyanide use than diseases or difficulties feeding them. I generally have little trouble with Calloplesiops altivelis, especially not with specimens from the Philippines where they have cracked down hard on cyanide fishing under Duterte (the one thing he surely did good).
I have massive issues with Calloplesiops argus, not getting them to eat but to keep a strange form fin rot and tissue deterioration from killing them. All of those come from Indonesia where cyanide fishing is rampant.