Aquarium Serial killers!

[binaryfuneral]

Twice:

1. Hortulanus Wrasse - Decided immediately upon arriving in the tank that it did not want any cohabitants. In a few days killed a juvenile longnose hawk, one of my firefish and beat up the other.
2. Falco Hawkfish - had it for a while was great first then decide to go after gobies. Grabbing them and swimming around with it in its mouth. Killed a diamond and de-eyed an orange spot goby. Had to remove all the rocks and coral just to catch it.

This is the exact experience I have had with hawks. Curious and unassuming until they snap and parade half-dead tankmates around in their mouths as a morbid warning to other peaceful fish.

 

[binaryfuneral]

I had a Splendid Dottyback for crazy. It first started gathering all the snails and killing them and stacking them in an area. Then it went at all the hermits, did the same with them. It then went at my trio of emerald crabs. After it was done it started going after the other fish in the tank. Nothing had changed in the system that I could see causing such a drastic change. It just became super territorial over night. I moved her to my sump and she passed away within 2 weeks without much difference than sporadic swimming at times.

Apparently that dotty was part Viking. Lining its “lair” with the carrion of its dead enemies is pretty metal.

 

[binaryfuneral]

Emerald crabs - Never again !!

I’ve sworn them off forever. Every time I have had a stressed wrasse or tang that just needed a moment to lay and rest, these guys pick them off. Never have sick or easily stressed fish with emeralds. Lesson learned.

 

[Machpoint89]

Emerald crab or hermit crab:

One of the two is a silent killer.

• 2 Pyjama cardinals
• 1 juvenile Scopas tang
• 2 watchman gobies

All killed within a day or 2 of introducing them to the tank.

since - the hermit crab has been banished to the sump. Next time I try to introduce a new tank mate I know it was the emerald crab (even though he’s got plenty to eat)

the original gang survived so far:

• 2 clowns
• Banana wrasse
• 2 cleaner skunk shrimp
• Purple dottyback

Conclusion

My best “guesstimate” it was opportunity feeding. I could be gone for weeks due to work and found out later that my autofeeder pump was clogged. So never dumped food in (although you’d think my GHA would be less over time)

manual supplemental feeding was performed, but just like “Bruce” (fish are friends …. Not food) I think the culprit had a “taste” for something after it’s first victim.

 

[binaryfuneral]

I had a Scopas Tang turn rouge and kill a yellow tang and was then going after other tank mates. Lucky for me he's also the easiest fish I have ever had to catch in the tank. Just a bit of nori in the trap and in he went without issues.

Never fun when a 70 dollar fish kills a 300 dollar one. I feel you.

 

[piranhaman00]

Need I say more…

Only other fish to go on an unprovoked killing spree was my banded leporinus. They have a need for dominance and kill any possible competitors (even passive fish like bala sharks). One of the best looking fish out there though:

Hard to blame any predators though, they are just doing what they were made to do.

I had a Lepo kill lots of fish as well

 

[Jubal_Harshaw]

Emerald Crabs. I had a bubble algae outbreak. I got them (3) and they took care of it. However, they also killed a Pom Pom Crab (I loved that little guy), and two Mexican Turbo Snails.

 

[DannoOMG]

I had a 6 line wrasse in my nano tank cause I had a flatworm problem. After my flatworms were wiped out he turned his attention to my watchman goby until he died.

A year later I think, the 6 line had his tail missing. I don't know how that happened. The ghost of watchman got him.

 

[WirelessMike]

Aquarium Serial killers!

Have you ever had a fish or invert go on a killing spree in your tank? (Could be a trigger that went postal or a shrimp that ate coral...or something else)

image source

Carpet nem. The silent killer. Had a small foxface fresh out of QT. Swam right into that sticky sucker and met his demise.

 

[Pearse73]

Banggai cardinal for me.
Between leaving for work one day and coming home, it flipped. Killed a blue green chromis , a red Firefish, and a Royal Gramma. It was in the process of relentlessly attacking a Lubbock’s fairy wrasse when I arrived.
Got it out but the wrasse was dead the next morning.
Always recollect this when people post about how peaceful cardinals are!

 

[Rp8]

I don't have actual proof but I think a tiger pistol shrimp went rogue and was picking my fish off one by one in the night.

I voted yes, had a murderous pistol shrimp turn on his partner goby, shot up about 6 hermits and royal grammar.

 

[Darkrooster]

Coral banded shrimp! And it’s still on a rampage cause I can’t catch the litter bugger!! I’m playing the long game now and biding my time…..

 

[flashsmith]

 

[Karen00]

Given my tank is just a 5g you would think it would be difficult to find a serial killer in a tank that small but I did. Up until about 6 months ago I only had a few small gobies and my precious Coral Croucher. One day I saw a cute Clingfish advertised at my LFS so I bought him thinking he was just a couple inches long. Well he turned out to be about 3.5" which had me a little concerned but most of his length seemed to be his tail and he seemed to have a tiny mouth so I cautiously added him. I was pleasantly surprised to see he was a model citizen. My small gobies were fine although admittedly they were too big to fit in his mouth. Fast forward to a few months ago and I added a couple smaller Red Head gobies. By the next morning one was gone. No body (alive or dead) to be found anywhere. I chalked it up to a possibly weak fish that got sucked into my pump area so I added another one. Same thing. Gone by the next day so now I'm thinking maybe the remaining Red Head goby killed both of his companions so I don't try another one. Then about a month ago I added two Flaming Prawn gobies. They were really tiny and within two days they were both gone (these losses really hurt). Now I'm thinking it might be my sweet Clingfish even though I have never seen him go near the gobies. Fast forward to a couple weeks ago and I had the opportunity to buy two small White Cap gobies and I'm thinking I'm not going to risk these guys in with the Clingfish so I frantically setup a 4g that I had lying around and put the Clingfish in there and added the White Caps to my 5g. I'm happy to report the White Caps are alive and well so my Killer Clingfish is forever banished to the 4g.

 

[ScubaShane]

Yes. In 2012 I added a Six Line Wrasse to my 250g and it attacked and killed 4 Clownfish and 6 Chromis in 2 days. He was not easily removed and rehomed.

 

[_sludgefactory]

My long nose hawkfish has killed almost every other fish that I've put in my tank but the green mandarin and the most recent addition naked cinnamon clown.

 

[Homey D. Clownfish]

My flame hawk was a model citizen all of 3 days until one day I woke up and all of my hermit crabs were missing. Didn’t hold it against him, though, as he was one of my favorite fish ever.

 

[DHill6]

A pair of ocellaris clown babies that would rip the glued acro frags off the rocks and drag them across the tank. I’d glue them back, they’d rip them off and deposit them across the tank. They were little battleships. After a couple weeks of this they were rehomed.

 

[OU812Reefing]

Aquarium Serial killers!

Have you ever had a fish or invert go on a killing spree in your tank? (Could be a trigger that went postal or a shrimp that ate coral...or something else)

image source

Yes Dam clowns NEMO is on angel killed 7 fish then Hurricane IDA took them out

 

[bguzio]

I had a blue throat trigger that was a very peaceful fish when he was a juvenile. However, when he got larger he started going after almost all of his tankmates. He was brought to the LFS and I received a credit for him.