night time violence - helpppp death toll at 3

Hi guys n gals,

Got a bit of a situation:

night before last i came down to my dead scarlet shrimp (he was about 2.5" so possibly old age) did water test and all at zero so put it down to age.

this morning came down and my mandarin was on the floor, it had jumped like 2" to get out the tank, my coral beauty was lieing dead on the sand.

hence did another test, nitrates hi all else normal (probably due to the fish lieing dead in the tank all night. so am doing a 30% water change at the mo.

another thing is my orange linkea has had a bite taken out of him and three of my small red leg hermits are dead half eaten with shells crushed

so i'm confused - this all started after fridays 20% water change, i added a mushroom coral and a pompom xenia after the water change.

any ideas anyone, is it possible that a rock inhabitant has grown large enough to start attacking my fish and causing havoc in the tank??

tank 42 gal
lighting 4* 38 watt t5
25kg of lr
tank set up nov 08
2* mp1200 powerheads
1* mp900 powerhead

inhabitants:
sailfin tang
true percula clown
blue damsel
orange linkia
blue leg hermit
electric flame scallop
reef lobster
2* turbo snail

corals
2* xenia (pompom
1* candy cap
1* toadstool
1* mushroom
1* green star polyp

 

So lets say that all water param issues and electrical current issues have been identifyed as not the issue,

All I notice on the livestock is the reef lobster. Is this a purple or red hawiian ? Either way, I dont know how they behave as I never had one, bet here is text from a site.

Possible exceptions are some invertebrates and some smaller bottom-dwelling fish. Lobsters should be kept one-per-aquarium, because they are territorial and intolerant of one another.

Could be, but who knows.


Good luck

 

hi, reef lobster is purple - they should be peaceful though apart from towards other lobsters

I'll see what happens over the next few nights and do some stealth spying, if anyone has any other ideas i'm wide open here.

Many thanks

Matt

 

In a 42 gallon tank, any tang might start to get very aggressive. I think this could be a massive coincidence. Fish jump sometimes and shrimp and fish die sometimes. I honestly can't think of anything else.

 

hi guys,

thanks for responses, i've done afair bitof reading up on this and have found the following.

Mandarin, sudden light flashs such as thunderstorms can cause these fish to jump from the water, i got in at 2am yesterday and opened the fridge swiftly to get a jug of water this could have caused the same reaction,

angel fish, unsure as this was good buddys with all but mandy including my tang, and no visible marks or sign of distress, maybe it was just his time?.

i completely forgot when writing this, i added a dog face puffer (day after shrimp died), as the mrs wanted one, and have a feeling this felt like trying some starfish and red leg meat

so all in all i think its all just one big coincidence still sad though me 2 most colourful fish have gone, still theres plenty more fiish in the lfs!!

 

I've seen fish jump out of water out of desperation of low O2 levels. Do you have a skimmer in your tank? What about surface agitation on the water? Those two things help support dissolved oxygen in the tank. When they are deprived of anything they need to survive, animals automatically go into survival mode and start weeding out the weaker ones.
As far as the shrimp, Iodine is a silent killer in inverts. I had a slightly elevated level of iodine and it wiped out both of my skunks in a hurry. I accidentally dosed Iodine one night when I meant to grab the bottle of calcium. It took 2 days after that to find the shrimp dead in the tank. That was just half a cap in my 20G tank to do it. That's probably not your case, but just in case you use iodine or iodide supplements.

 

look this up, but i think you can use a red light to look at the fish at night because they can't see red.

 

Mandarin's do have the ability to jump out of water. While they are not know to be rampant jumpers, theres a couple of people right here on this board that have had them jump.
As for the others, I'd say with almost certainty that its the lobster. They are predatory and opportunistic, whether they be red, yellow, blue, purple, whatever. I know of 3 different tank owners here that have tried to keep purples because they are "safe", only to have them kill other tank inhabitants, including sleeping fish. IMHO, lobsters have no place in a community and/or reef tank, no matter what color they are.
The other thing that could factor in is you said your nitrates were high. Exactly how high are we talking about here?

 

wow i am sorry to hear about the lost, i luv both maderins and CB. But i would say that it seems like there is too many coincindences in such a short time.

IMO you probly lost the inverts to either the lobster or puffer, the lobster seems like the culpret. but for the CB to not have any marks is what concerns me, that with the mandrin jumpin out. something is going on. what did you test for exactly? and what type of water are you using for your water changes?

 

Thats crazy. Aquariums are takeing over midnight snacks to. =)