Killer Banggai?

[csreed]

Hello, everyone.

A week ago I tore all of my aquascaping down in an act of massive frustration. I caught 2 of the huge polychaete worms I was hunting but never found the third so I finally took all the rock that didn't have something valued encrusted on it & left it out to dry. This means I have very little rock in my 200 gal tank. (I'm adding rock back slowly to avoid a massive cycle.)

So, here's the problem: someone is tearing my fish apart at night & I think it's my Banggai. I've lost a peppermint shrimp, the non-dominant Banggai, & now my beloved yellow-head jawfish. Everyone is fine when I go to bed at night...

I have a 200 gallon tank with a flame hawkish, some blue chromis, a royal basselet, a dragon goby, 2 clownfish, a yellow tang, & a big fat Banggai.

Do I get rid of the Banggai? Anyone else had one go for their other fish (besides another Banggai)?

Thanks for any input - I'm in mourning... [emoji22]

 

[Desmond]

I have a banngi in my tank and have never seen it go near anything. Even when I have introduced new fish. I have heard of them attacking fish before. Could it be your tang by any chance ? Have you seen the banngi being aggressive towards other fish ?

 

[csreed]

I've never seen the tang misbehave & he seems pretty dormant at night. The cardinal fish has been aggressive to the other cardinal but I haven't seen him mess with the other fish. All of my casualties have been really chewed up...

 

[4FordFamily]

I would be absolutely astonished if the cardinal was the guilty party here. Given the other tankmates I can't be sure, but it may be a crab of some sort of not the tang, and it probably isn't.

Bangai certainly can and will kill each other at times, but other than that they're very docile

 

[NanaReefer]

Although he's never bite the 6Line my Banggai sure keeps him in his place, never bothered my Gramma and pays no attention to my YWG.
However this you say is happening at night? I'd get a red light and grab a seat after lights out. Possibly you got an night predator.

 

[Reef_a_holiks]

Funny you bring this up, I ran into a almost identical case ,though my banggaii only killed its partner. I had two banggai cardinals ( a pair) , that always got along with each other and the other fish. Extremely peaceful fish, even had babies twice. When upgrading tanks, I removed about 3/4 of the rocks out to transfer into the new tank and the next morning I noticed one of the banggaii cardinals extremely aggressive, it surprised me at first , as ive never seen this fish act this way. It was mostly aggressive towards its partner, and just a bit territorial towards the other fish. I decided to put some rocks back in, hoping it will calm him and and give the fish more hiding space. That same night I found one of the cardinals dead and chewed up by its partner. Never seen this kind of behavior before by a cardinal. I immediately took him out and transferred him into another tank by himself to prevent him hurting any other fish. Fast forward about a month later, the new tank is running and I introduce the cardinal again to the new tank and the rest of the fish and hes back to normal, and very peaceful. havent had any problems with him ever since.

Not sure what got into him back then, maybe they feel threatened when taking down their territory and causes them to act aggressively. Was kinda ticked I lost the mating pair. I say remove him, before he harms any more fish .

 

[Desmond]

I would not rule out the flame angel either as they can be very territorial also. Mine was fine but did not like new fish. Also I think looking for a crab may be no harm. As said you could sump the banggai for a month and see if he cools off or if your fish are still getting attacked

 

[eatbreakfast]

Not noticing aggression during the day, but something 'tearing them up at night' is an important clue. Hawkfish and tangs are diurnal, so won't be involved in aggression at night. Bangaii's are crepuscular and more active in the evening and noght, so could quite possibly be the aggressor. While the evidence points to the bangaii, a crab of some sort can't be ruled out yet either.

 

[Paul B]

I am sure it is not your bangai. I have a pair now from babies and I also have clown gobies, shrimp, and a few tiny pipefish and even now that my bangai's are huge, they are the most peaceful fish there is. I have been keeping them since they discovered them and never had any problems. You may have a Loch Ness Monster larvae or something else.

 

[eatbreakfast]

For the most part bangaiis are peaceful, but can be quite aggressive with conspecifics, and in rare, though not unheard of cases, can be surprisingly aggressive toward other peaceful tankmates.

Again, the timing of the aggression is important, as it it is occurring at a time that most of the fish bunker down for the night, so the guilty party has to be comfortable at night. A bangaii is quite comfortable at night.

 

[csreed]

I can't catch the cardinal fish - speedy maneuverable little booger! But I added in a bunch of rock last night & this morning there were no casualties - whew! I'm pretty sure there's nobody else lurking unless that miserable polychaete worm survived. He ate all my snails but didn't seem to bother the fish. At least, I'd been hunting the worms for a year & hadn't been losing fish. My husband thinks I'm nuts with how much time I spend with a flashlight looking in the tank at night. It's possible I'd miss something, but I'm doing an awful lot of looking...

 

[NanaReefer]

Try netting him at lights out. Much much easier.
When hunting for critters a night, use a red LED flashlight.
https://www.amazon.com/Carson-StarMap-Flashlight-Low-Light-SL-11/dp/B000WG0LPQ

 

[Desmond]

Strange alright. Mine is a good size also and is very peaceful. If only my bloody female clowns was not such a nut job. Any time I add new corals she attacks me nonstop. No fear at all.

 

[sanchoy]

Banglai will only bother other similar species. Never seen one actually injure another, just showing off by chasing.

 

[csreed]

So, the killings continued until I caught the cardinal fish. It's been a week, & not a single injury since he went in the overflow box...

 

[izzyishh]

I went thru the same thing!!!!! Its crazy how a so called "peaceful" fish ends up being a psychopath mine killed its partner and went on a rampage murdered a few of my gobies i exiled it to the back chamber of my biocube

 

[Mark Gray]

I had a powder blue tang do this at night took me a while to figure out it was him very peaceful in the day time

 

[lewis.maryann08]

I had a Banggai in my tank and it was the same way it try to kill my fish also it was really mean so i took him to my lps

 

[RMS18]

My cardnialfish is the peace keeper of my system. She will go and break up any aggression. I have a basslet who will sometimes be territorial. The cardnialfish will dart over and bump her body into the basslet when he goes after another fish.