Murderous lawnmower blenny?

[ntropics]

Yesterday in my 30 gallon quarantine tank: 3 very healthy royal gramma and one lawnmower blenny. Today one dead, chewed up, royal gramma, one healthy lawnmower blenny and nothing else.

I am assuming the blenny is the culprit, i.e. he killed all three royal gramma, and ate two, in which case he will not go into my display tank next month. Any other thoughts?

I have a tight fitting top on tank, so no jumpers, for sure.

Thanks.
Bruce

 

[fairl80z]

I have a lawnmower blenny and he is the sweetest thing ever . I'm thinking that your royal gramma tore one another apart

 

[SaltyDoug]

What do you have for a clean up crew?
You sure they didn't get torn up after their demise?

Royal gramma can be territorial with each other if they don't have their own space to call home.

 

[ThRoewer]

I had 3 gramma in a 10 gallon QT for 6 months and there was not even as much as a shredded fin. There was only some chasing and pretend fighting

 

[MaLi]

... I had once a blenny and every other fish had a round mark from his mouth time by time. It was like a pet following your finger over the tank, but if you have small fish ... give blenny away.

hope it helps,
MaLi

 

[ntropics]

Well, no clean up crew in the QT. I spoke with the owner of Unique Corals, from whom I got the four fish, and he stated that Royal gramma do not fight with each other. From what I saw in the QT for four weeks, that is correct. there were no skirmishes between them, but I have heard tales of occasional blenny aggressiveness.

Not sure where to go from here. My tank is a 200 so the blenny would have plenty of room, but I don't have any desire to add an aggressive fish to my tank, that has the potential to harm other fish, and that would be a pain in the neck to try to remove later (LOT of live rock to hide in).

Bruce

 

[lucky_snapper]

I had a lawnmower blenny in my 225 and had no issues... he will have plenty of room to roam and graze.

 

[scooter31707]

I don't think the Lawnmower Blenny may be the one. On that note they are considered to be the most aggressive of all the Blennies.

 

[fairl80z]

It is so hard for me to believe that a LMB did it . Mine is about 5 1/2 inches long and I used to keep him in a 15 gallon tank with a small clown fish . No aggression what so ever .

 

[fearyaks]

I've seen a Lawnmower Blenny at a store chowing on a dead fish. Is it possible he was just hungry and the fish had died from other causes while in quarantine?

 

[ThRoewer]

It is so hard for me to believe that a LMB did it . Mine is about 5 1/2 inches long and I used to keep him in a 15 gallon tank with a small clown fish . No aggression what so ever .

There are always exceptions where some wiring in the brain has gone wrong. Like sociopathic serial killers among humans. I can imagine similar things among animals (though most animals have a better sense of abnormality and no issues with eliminating them before they become a threat).

 

[fairl80z]

There are always exceptions where some wiring in the brain has gone wrong. Like sociopathic serial killers among humans. I can imagine similar things among animals (though most animals have a better sense of abnormality and no issues with eliminating them before they become a threat).

I've never really thought about it like that haha!

 

[bob1968]

Those fish should be kept by themselves.
They fight each other.
Store owner probly said that to cover his you know what

 

[ThRoewer]

Those fish should be kept by themselves.
They fight each other.
Store owner probly said that to cover his you know what

Which fish? The Grammas? You can have a whole bunch of them together as long as there is only one male. Only males actually fight with each other.

 

[ntropics]

Well, I finally figured it out. It's not a murderous blenny, it's a murderous AQUARIUIST! I found one more dead gramma, and one dying -- I guess they were hiding -- neither of them were bitten or ripped up, just a bit frayed at the tail. I thought, okay, it's time to check the water parameters. So what did I find? I had an ammonia spike at .25!

I guess the gramma are more susceptible to elevated ammonia than the blenny. I did a large water change, then added Prime. The ammonia now reads zero. So it was MY fault! I'm pretty angry with myself for not thinking of that at first, and for killing three beautiful fish. I've never had a problem with elevated ammonia in my QT before, so I figured I would be safe. I only checked the ammonia the first week, and since it was normal, forgot about it.

Thanks for all the help. I guess the blenny is safe after all, and quite hardy. Me safe? Not so sure!

Bruce

 

[Dkuhlmann]

Get one of the ammonia badges, it will save you the trouble of testing ammonia all the time.