HELP! Disappearing fish

[SarahW]

Hi,

So I've now had my River Reef 94 litre running for 5 months. All had been going well, have 10kg live rock, purigen and phosguard in the back as well as 2 pumps, power head and filter wool.

Stocking wise had 2 clownfish and a couple of months ago I got a tail spot blenny.
CUC wise 3 red legged hermits, one cleaner shrimp and 3 turbo snails.
I do occasionally see bristle worms, small white stars (literally millimeters big).
Have got several corals: Duncan, zoas, Xenia, toadstool, finger leather, mushrooms, green stars.

So all seemed fine until I woke up one morning to find tail spot blenny was missing. Searched all the back compartments (no sump or anything) under rock, everywhere. Not a trace.

Water all fine (0 ammonia, nitrate, nitrite, very low phosphate). SG 1.025.

So I put it down to bad luck. Then bought a yellow clown goby. Fine for a month, until one morning found one of my clownfish was gone. Also no trace.

Ended up replacing clownfish so back to 2 clownfish (which get on well) and the yellow goby. All fine for the next week until I got up this morning having seen all 3 happy, eating brine shrimp I fed the night before, to find no goby . Again nowhere to be seen.

I'm getting really disheartened as I don't know what could be happening? They seem so well before they disappear?

Have been through a few options suggested when googling the problem, but it's got a closed lid and no bodies ever found nearby the tank, I never hear clicking at night and would be surprised if one was there as only a small tank with 10kg Rock to hide in. Bristle worms I've read will clean up but unlikely to kill.

Then I thought my coral could be killing them somehow? If so I have no idea which one?

I'm close to giving this expensive hobby up as I can't keep replacing them for them to meet a short end...!

Thanks for any help.

 

[sirrealism]

Where did you get the rock? I would think you have a hitchhiker thats eating your fish.

 

[SarahW]

At my local fish shop. Was fully cured.

What do you think could kill them? Could a bristle work become big enough to attack?
And how can I find out before any more die?!

 

[mtsully71]

Agree with sirrealism, Where and how did you get the rock and my first thought is you have a nasty hitchhiker. The only other thing I can think of is verifying the fish cannot get into anywhere and any thing that might be mechanical they cannot get stuck or chopped in. The fact you can produce no body, indicates you likley have 1 of the 2 problems above.

I would inspect your rock very close.

 

[sirrealism]

Are your corals mounted to the rock? If not I would take the rock out a few pieces at a time and put them in a 5 gallon bucket with fresh RODI water in it for about 1/2 an hour. Should not hurt the bacteria on the rock and should force out an hitch hiker. I might be wrong on this and I hope someone else will chime in if they think the 30 min is to long.

 

[SarahW]

Some corals are attached pretty firmly, and some new ones are growing directly on the rock...so it'll be tricky to do as suggested. I can try if it will help though! Scared of killing off good bacteria and crashing the tank and killing off fish/cuc...?!

 

[DaveK]

Are your corals mounted to the rock? If not I would take the rock out a few pieces at a time and put them in a 5 gallon bucket with fresh RODI water in it for about 1/2 an hour. Should not hurt the bacteria on the rock and should force out an hitch hiker. I might be wrong on this and I hope someone else will chime in if they think the 30 min is to long.

This is something you should never ever do. You'll kill the entire bacteria base on the LR. It only takes a few seconds in FW to do that.

If you can get this down to 1 piece of rock, then maybe, just to get the hitchhiker, and realizing what your doing to the rock.

 

[DaveK]

At my local fish shop. Was fully cured.

What do you think could kill them? Could a bristle work become big enough to attack?
And how can I find out before any more die?!

Even though you got the LR from your LFS and it was cured, you can still easily get an unwanted hitchhiker. Yes, some bristle worms can get big enough to attack a fish. I once removed one about 2 feet long from my tank. However, most of them are not a problem. You want to be looking something like a mantis shrimp, or possibly a cone snail.

 

[nanoreefing4fun]

On the yellow clown goby, another possibility is he was sick from the start & succumbed to a sickness or some parasitic intestinal infection and starved to death... one never knows for sure...

If this were the case... a cuc (clean up crew) can easily dispatch of the remains overnight and you can never see a remnant, especially if he was back in the rock work.

This is just another possibility & one where you did nothing wrong - I lost a yellow clow goby & beleive this to have been the case...

sometimes they have damage from being trapped or how they were caught and only live a short time, like a month before the sickness overcomes them

So don't feel bad or give up, when you are trying your best... also great advise from all above ^

 

[SarahW]

Thanks for the replies.

Thing with the clown goby is I watched him eat right up until the night he vanished. Was taking frozen brine shrimp along with the clownfish. I just thought I'd see a decline rather than sudden death.

I do wonder though, if I do have a killer lurking in the rock, why hasn't it go to my snails, hermits or shrimp? My clownfish sleep floating at the top of the tank so I can't imagine how he would've been eaten?

Been hunting tonight, have seen a pretty big bristleworm, should I try and remove? Also some brittle stars which are quite small.

 

[Surfnut]

Do you hear any clicking in the tank at night when the lights are out? you may have a pistol shrimp or Mantis shrimp. Could also be a large crab hiding in the liverock. And yet there are some worms large enough and mean enough to eat larger fish.

 

[SarahW]

No clicking sounds...surely with only 10kg rock it would have a hard time hiding? Also my snails, hermits and cleaner shrimp are all ok?

So have continued to watch my tank by night and have discovered I have a lot of "digitate hydroids" growing off the rock. Could these have killed my fish, and the Cuc polished off the bodies..?!

So close to stripping the whole tank, killing all the live rock and restarting. Just don't know what I'd do with my clowns, coral and Cuc if I did that...

 

[Snelly40]

maybe the clowns beat them up... clown gobies are very small and blennies as well.. clowns are territorial and that's a small tank... tank size is also why im not leaning towards a nasty hitchiker that would take out 2 fish...

also, what do you feed other than the brine shrimp you mention? the fish that dissapeared are also very highly metabolic fish and brine is like popcorn, it tastes good but no nutritional value...

and dont restart... not sure why that would be an option...

 

[SarahW]

maybe the clowns beat them up... clown gobies are very small and blennies as well.. clowns are territorial and that's a small tank... tank size is also why im not leaning towards a nasty hitchiker that would take out 2 fish...

also, what do you feed other than the brine shrimp you mention? the fish that dissapeared are also very highly metabolic fish and brine is like popcorn, it tastes good but no nutritional value...

and dont restart... not sure why that would be an option...

Thanks for your reply. Yes I did think it would be odd. Have lost 3 fish now - clown, Blenheim and

 

[SarahW]

My phone went weird!

I meant blenny and goby as well as clown. The blenny was bigger than the clown though. When I introduced a replacement clown he went for him for the first 24 hours, but they get on fine now. He never seemed to go for the other fish I've lost, they always disappeared at night having looked fine the evening before...

I feed hikari marine S as well as brine shrimp.

The reason I would restart would be to kill the live rock of all it's inhabitants (bristleworm and digitate hydroids, of which I've discovered loads) but obviously this would crash the whole tank so don't really want to have to.

Just hate not knowing what's happened for sure!

I've read other people can keep a pair of clowns and one or two other smaller fish in the River reef 94 so I'd be disappointed to only be able to keep the clown pair, but I will if people think my clown could be to blame...?

 

[Oxylebius]

Most likely you have a nocturnal predator hiding in the rocks. All predators previously mentioned by other posters are possibilities, one additional one I'd add to the mix are swimming crabs. Swimming crabs are also nocturnal and are fish eaters.

Have you tried to look at the tank in the middle of the night with a red light. After the lights of the tank (and the room the tank is in) have been out for several hours. Most critters won't see red light. Looking with a white light can make this predator hide, but it wouldn't be able to see red light. Using a red light allows you to observe the tank w/o freaking any critter out.

 

[Snelly40]

^^ @Oxylebius def knows his/her stuff!!
If Sarah doesn't have a red light, will red Saran Wrap work to cover a flash light?


Sent from my iPhone using Tapatalk

 

[lbiminiblue]

Yeah this can't just be a fish hiding. Look for a worm or a mantis shrimp. My other guess would be a pistol shrimp.


And yes, 10kg is small, but most Calcium Carbonate rock formations have LOTS of small tunnles and crevices to hide in. A big bristle worm in a small tank could easily wrap itself around in a pocket in the rock and hide until night.


Same for pistol shrimp.


If you do decide to take your rocks out to search for a hitchhiker, which I think you definitely have, use gloves.


Any creature that's killing those fish is most likely big enough to hurt you. Bristle worms can prick you with those fiberglass type spines. Be careful.


If you find the critter with red light, let us know. From there its planning the removal/trapping. If its a worm it shouldn't be too hard.

 

[Oxylebius]

I have a headlight that has a red light setting - which works wonderfully. They are fairly inexpensive and easy to come by, any outdoor sports type store should carry them, here is one on amazon.

You can try saran wrap on a flashlight and see if that works. You have have to double (maybe triple) the saran wrap (maybe not), this might be trial and error until you get the amount of red light needed.

Agree with Ibiminiblue - Once you find the critter with red light, let us know. From there we can help with planning the removal/trapping. But first, we need to find the culprit.

 

[lbiminiblue]

Its simple. We kill the batman.