Is a box fish for my tank bad?

[Spookyclemente]

Hello! I currently own a 125 gallon aquarium.
I have a few blue damsels with yellows tails a clown fish a fox face a sailfin and a butterfly and a snowflake eel who is super super chill. Basically a puppy.
I just recently picked up a long horn box fish
But now I’m just reading they can completely nuke and kill all your fish?!
Is there truth behind this or not really?
I read a few forums and didn’t see anything about this but I just watched a video and I’m hearing this now.

 

[i cant think]

Hello! I currently own a 125 gallon aquarium.
I have a few blue damsels with yellows tails a clown fish a fox face a sailfin and a butterfly and a snowflake eel who is super super chill. Basically a puppy.
I just recently picked up a long horn box fish
But now I’m just reading they can completely nuke and kill all your fish?!
Is there truth behind this or not really?
I read a few forums and didn’t see anything about this but I just watched a video and I’m hearing this now.

Yep! This is true - If these guys die whilst stressed they leach a toxin that can nuke a tank.

Some are more known for it than others and I believe the Yellows are less likely. Also do you know about their adult colouration being different and their size being over a foot long?

 

[Spookyclemente]

Yep! This is true - If these guys die whilst stressed they leach a toxin that can nuke a tank.

Some are more known for it than others and I believe the Yellows are less likely. Also do you know about their adult colouration being different and their size being over a foot long?

Crap…is this something I should be very concerned about?
I have him in a quarantine right now.
I knew that their color can change but their size I had no clue…I was under the impression they only get a few inches…

 

[Spookyclemente]

Yep! This is true - If these guys die whilst stressed they leach a toxin that can nuke a tank.

Some are more known for it than others and I believe the Yellows are less likely. Also do you know about their adult colouration being different and their size being over a foot long?

 

[i cant think]

Crap…is this something I should be very concerned about?
I have him in a quarantine right now.
I knew that their color can change but their size I had no clue…I was under the impression they only get a few inches…

From memory they’re fairly active so a 6’ tank may be sufficient but as they age that’s the only way to be certain.
They’re also rather sensitive to Ich.

The species you have is a long horn cowfish which is the same issue as Box Fish but they get 20 inches. I can’t remember much on their growth rate though.

 

[Spookyclemente]

From memory they’re fairly active so a 6’ tank may be sufficient but as they age that’s the only way to be certain.
They’re also rather sensitive to Ich.

The species you have is a long horn cowfish which is the same issue as Box Fish but they get 20 inches. I can’t remember much on their growth rate though.

I have him in a prazi pro treatment right now to make sure he is in good health before going into my main tank. He seems super Healthy and eats like a nut. But this whole nuking thing has me very worried.
I have a GSP but he hasn’t grown in YEARS and he’s super super healthy

 

[i cant think]

I have him in a prazi pro treatment right now to make sure he is in good health before going into my main tank. He seems super Healthy and eats like a nut. But this whole nuking thing has me very worried.
I have a GSP but he hasn’t grown in YEARS and he’s super super healthy

I’d be more concerned with a Cowfish nuking the tank, but there’s always a chance it won’t happen. These guys also don’t seem to care too well in extremely high flow so make sure there’s some good weaker regions of flow in the tank.

 

[Spookyclemente]

I’d be more concerned with a Cowfish nuking the tank, but there’s always a chance it won’t happen. These guys also don’t seem to care too well in extremely high flow so make sure there’s some good weaker regions of flow in the tank.

So I looked into their growth rate. It seems like it’s slow but I could be wrong. He’s maybe 3 inches but I just had no clue they can get up to 20 inches. Maybe this is gonna be one of those take it as it goes type things. See how he does the first few days in the 125. And if he does great I’ll keep him for as long as possible worse comes to worse if he gets too big I’ll get him a new home.
Very very worries about the nuke but I do have poly pads in my filter and a skimmer and 2 filters so hopefully that can keep me covered.

 

[PharmrJohn]

This very well may be a stupid question, but can you take it back? If so, I wouldn't hesitate.

 

[Paul B]

I have had many cowfish over many years and they all eventually died in my reef. Nothing ever happened to the rest of the fish but I know they are very toxic. I am just not aware of that ever actually happening.

But I have seen them over a foot long on the reefs.

 

[ISpeakForTheSeas]

But now I’m just reading they can completely nuke and kill all your fish?!
Is there truth behind this or not really?

It was discussed in the link I shared in your other thread - here are the highlights:

Just to clarify here, boxfish/cowfish actually have to be alive (and stressed) to produce their toxins - they can't physically produce the toxins when they're dead.

No experience with keeping them myself, but, for boxfish specifically, these guys aren't toxic when they die, they're only toxic when alive and stressed (they have to be alive to produce the toxin, and they only produce it when stressed). The toxin they produce is a potent ichthyotoxin called Ostracitoxin or Pahutoxin (ichtythoxin meaning it's a toxin that primarily effects fish, though this toxin has been demonstrated to slowly affect a wide variety of inverts too). In small quantities, the effects may be mild as long as the toxin is promptly removed, but the effects of it on fish are irreversible (meaning the fish - if they heal from it at all - will recover over a long period of time, and they will only recover if the damage is mild and the toxin is no longer present in their environment).

When the toxin is present even at 5ppm in the water (the equivalent - if my math is right - of ~3.4ml of the toxin in a 180 gallon tank), 50% of the following species of fish died within the following times*:
Abudefduf abdominalis - 6 minutes
Acanthurus sandvicensis - 8.5 min
Kuhlia sandvicensis - 10 min
Mugil cephalus - 12.5 min
Mollienesia litpinna - 15 min
Bathygobius fuscus - 30 min

Given that the damage is irreversible and lethal even at relatively small doses (and that boxfish themselves aren't immune to the toxin, though they are more resistant to it than other fish), I'd guess it's probably not an overblown risk (though it is something you could likely try to prepare for by running carbon and having a water change and QT ready at all times).

That said, I don't know how fast these guys produce the toxin, but as long as the fish doesn't get too stressed, it should theoretically never produce enough toxin to cause an issue (though I'd constantly run carbon on the tank just to be safe).

* The study I pulled the data from:

Toxic Stress Secretions of the Boxfish Ostracion meleagris Shaw on JSTOR

Donald A. Thomson, Toxic Stress Secretions of the Boxfish Ostracion meleagris Shaw, Copeia, Vol. 1969, No. 2 (Jun. 3, 1969), pp. 335-352

www.jstor.org

For anyone scared by the numbers in the quote above:

I’ve kept various box fish over the years. The only time I’ve had issues with toxins were with boxfish I had just caught myself and placed in buckets on the boat.
That said, this is one of those fish that appear to do fairly well, but asking who has kept one longer than two years, not many hands in the air. The only ones I have had long term success with were temperate Australian species.

Jay

I also haven't heard of any confirmed "nukes" by these fish; as you said, the risk is there, but given a decent environment, the risk seems to be quite low.

 

[Jay Hemdal Verified Community Expert]

Hello! I currently own a 125 gallon aquarium.
I have a few blue damsels with yellows tails a clown fish a fox face a sailfin and a butterfly and a snowflake eel who is super super chill. Basically a puppy.
I just recently picked up a long horn box fish
But now I’m just reading they can completely nuke and kill all your fish?!
Is there truth behind this or not really?
I read a few forums and didn’t see anything about this but I just watched a video and I’m hearing this now.

I've never had a longhorned cowfish release toxins in an aquarium, not like boxfish can do.

However, cowfish are really prone to ich and seem to arrive with a lot of diseases. They also don't thrive longterm in most aquariums. I think my record is around 3 years, with 12 months or so being the norm.

 

[Spookyclemente]

I've never had a longhorned cowfish release toxins in an aquarium, not like boxfish can do.

However, cowfish are really prone to ich and seem to arrive with a lot of diseases. They also don't thrive longterm in most aquariums. I think my record is around 3 years, with 12 months or so being the norm.

Alright that good to know.

Do you think I’ll be safe with mine in a 125 for right now? He’s maybe 2 or 3 inches.
I have him in the prazi and I’m gonna start and try the metro

 

[Spookyclemente]

I have had many cowfish over many years and they all eventually died in my reef. Nothing ever happened to the rest of the fish but I know they are very toxic. I am just not aware of that ever actually happening.

But I have seen them over a foot long on the reefs.

Do you have a idea of their growth rate?

 

[Reeferbadness]

I've had 2 cowfish. 1 lived for about 2 years and got pretty big but ended up lodging himself in a rock next to a nasty coral and i think it stung him to death. No toxins released. The 2nd one was pretty young, about 2 months in my established mixed reef tank and ended up getting a bad case of ich and died. Also no toxin released. There was a very aggressive emperor anglefish with the younger cowfish but he left him alone (wisely). I wouldn't be too concerned.

 

[Spookyclemente]

I've had 2 cowfish. 1 lived for about 2 years and got pretty big but ended up lodging himself in a rock next to a nasty coral and i think it stung him to death. No toxins released. The 2nd one was pretty young, about 2 months in my established mixed reef tank and ended up getting a bad case of ich and died. Also no toxin released. There was a very aggressive emperor anglefish with the younger cowfish but he left him alone (wisely). I wouldn't be too concerned.

Alright this really makes me feel a lot better.
Mine is about 2-3 inches. Eating well. Great color. No ich but I have him in prazi for a little while to make sure he is healthy.
I’m gonna be adding him to my 125. Is that gonna be okay?

 

[Paul B]

Do you have a idea of their growth rate?

No, but in my tank they never grew to big even after 2 years. I don't remember how long I kept any of them because I haven't had in many years.

 

[Jay Hemdal Verified Community Expert]

Alright that good to know.

Do you think I’ll be safe with mine in a 125 for right now? He’s maybe 2 or 3 inches.
I have him in the prazi and I’m gonna start and try the metro

Depends on the tankmates. The tank size is fine, they grow really slowly in captivity.
I’d skip the metro, it is really overrated for treating external protozoans, it also isn’t safe with most invertebrates.

 

[Spookyclemente]

Depends on the tankmates. The tank size is fine, they grow really slowly in captivity.
I’d skip the metro, it is really overrated for treating external protozoans, it also isn’t safe with most invertebrates.

I have a few damsels that don’t bother anyone but eachother at time when they go into others houses but when they then that they all get along.
I have a sailfin tang, a fox face, and a butterfly and a gsp who is rather small and just sits with sand on his head lol.
I also have a snowflake eel who I have had for a few years and he is the nicest and more peaceful eel.

 

[TheGrimReeferTx]

Crap…is this something I should be very concerned about?
I have him in a quarantine right now.
I knew that their color can change but their size I had no clue…I was under the impression they only get a few inches…

I've been on this thread for not too long, and have seen several posts about these fish nuking a whole tank.
Just watch your tank closely.