Killer fire shrimp???

xokarmaxo

Member
My fire shrimp was one of the first inhabitants of my tank 3 months ago. (Oceanic Biocube 14). Gorgeous shrimp. I've always heard that they are usually nocturnal and that some people who have had them almost never see them. Well, mine is the opposite. It is always in plain view, front and center of the tank, perching on the rock, hanging upside down under a rock, sifting through the sand, etc... Not shy at all. I decided a month after I got him to add another one. He chased the other one all the time and then after a week or so, they seemed to be "buddies".... perched side-by-side on the rocks, following each other. I was pretty happy with that. Early last month I came into work (where my tank is) and saw that the 2nd added shrimp was totally butchered. Looked like something shredded him up. The other shrimp was right next to it and when I put the skewer in to remove it's remains, the other shrimp jumped up and grabbed a hold of it and tore into it. I started to wonder if this shrimp killed the other one.
Fast forward to last weekend.... just 2 days before, I added a purple firefish. She was so beautiful, but very shy and preferred to stay in the back of the tank hovering behind or under the live rock. Came into the office over the weekend to check on my tank and the firefish was nowhere in sight. Moved every rock, looked in all the back compartments, on the floor (even though my tank is covered) everything.... couldn't find her, so I assume she died sometime between Friday evening and Sunday morning.
Then.... last Wednesday, I added the cutest little bicolor blenny. He found many little holes in the live rock to hide in and peek his little head out watching everything. He never bothered anything. Just the most adorable little fish. This time I witnessed my fire shrimp being aggressive towards the blenny. When the blenny would go down into the hole, the shrimp would perch right next to the hole and when the blenny would stick his head out, the shrimp would ambush him and just take his claws and look like he was trying to beat the poop out of him. I have a little pom pom (boxer) crab and even he would be a bugger to the little blenny. The blenny would always pop back down into the hole.
Imagine my surprise when I went into work to check on my tank this morning and didn't see the blenny. I looked everywhere. I noticed that my cleaning crew were all in the center of one of my rocks and my heart sank. I took the skewer to push the crew away to see what they were nibbling on, and yep, it was my sweet little blenny. As I was removing his remains, the shrimp tried to grab onto it.
All of this is making me wonder.... is my fire shrimp a murderer???? Is he the one that killed my other shrimp, the firefish and the blenny??
I also have a true percula and a sixline wrasse (sixline added yesterday and is just as sweet as it can be, minding its own business) that are doing great. My water parameters have always been fine when I test them, so I don't know what else it could be??

Do you think that when these smaller, shy, "stay-near-the-bottom" not as active fish go to sleep or whatever, that my shrimp attacks them and kills them?

If this is the case, or if anyone else has experienced something like this, please let me know. I want to try again to get a bicolor blenny, but will take my shrimp back to the LFS if anyone else thinks he might be a killer.
Any and all help is greatly appreciated!
 

anonome

Active Member
I honestly don't think that your fireshrimp has killed anything. They are opportunist, not killers. If something is dieing then they will get their fill, not the reverse.
You said that your parameters where great, but didn't test for this. You have had a lot of fish die. That would be the first thing I would test for.
Are you sure the carcass you found of the other shrimp is a shrimp and not a molt? Shrimp are very sensitive to changes in the water, you said you just added this shrimp.
List your parameters and maybe we can help.
 

xokarmaxo

Member
OOps, sorry... My parameters were the following:
Temp 80.9
Ammonia 0
PH 8.2
Nitrite 0
Nitrate 0
SG 1.024
Salinity 32
Calcium 450
I haven't had "a lot" of fish die, just the one bicolor blenny whose actual carcass I removed, and I "suspect" that the firefish also died and was consumed because I never found a trace of it anywhere.

The other shrimp I am sure died because I removed the carcass and it was not the molt, it had the meat still inside, and the shell was solid.
Sooo.... I don't know. The shrimp brings a lot of color and personality to the tank, but his witnessed "agressiveness" towards the blenny is what makes me wonder....

Thank you for taking the time to post a response.

BTW... I do 20% water changes every weekend using Nutri-Seawater, top-offs with R/O water. The only supplements that I add to my tank are Kent Marine's Zooplex, Kent Marine's Tech I and Purple Up for calcium.
 

boozzbro

Member
i doubt your fire shrimp killed any of the fish. i do however believe it may have killed the other shrimp.
like it was staked above they typically wont kill to feed. they will eat what they can. if they fish are wear/dying they may pick at them and make the situation worse. but they generally wont go "hunt" your other fish down.
Fire shrimp can be aggressive towards their own kind if they arent introduced at the same time.
 
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