Moray eel mystery death

[tuajia]

Hi all, just sharing my recent bad experience over the weekend. Although it is a brackish tank, I believe more people here keep moray eels so i hope that my loss can provide useful info to fellow moray eel keepers.

I have been keeping some moray eels of various species together in a brackish tank at SG 1.010 for the last 4 months. I have gymnothorax tile, gymnothorax polyuranodon and one gymnothorax fimbriatus which was my latest addition. (he was sold as "freshwater" so i am in the process of converting him back to marine). I feed them once a week with pellets and some mixed seafood. Here's a pic of them

They were doing ok for the last few months when suddenly i came back last friday night, i noticed that all the eels (except my fimbriated moray, which is barely 1 week in the tank) were "standing up" and poking their heads out of the water. I also noticed the water was a bit cloudy. I quickly assumed it was a bacterial outbreak and quickly did a 50% water change. All seemed well.

Next day, my gymnothorax polyuranodon had turned white and died

I panicked and did a 20% water change again. I also tested the water - No ammonia, no nitrite (didn't check nitrate). What could be wrong?! Disease?! I searched on Google but found little info. I tested feeding response - it was quite bad, only 1 guy wanted to eat. Funnily enough, only my fimbriated moray seemed ok. I quickly isolated him in another tank. Water was still cloudy.

Sunday came, another 2 gymnothorax tile dead, including the one that was eating normally. Sigh. With nothing to lose, I decided to remove the last guy, isolated him in a pail and dosed OF yellow powder (i used it to treat my other fish for bacterial infections before). He seemed ok at first, but by Monday morning, he was dead too. So officially, all of my 4 original eels are dead.

So now, only my new fimbriated moray is still alive. I am keeping him in a bucket for now, changing water every day. I also took pictures of the dead eels, hoping to find some answers. WARNING, they are a bit disgusting, so I have posted links instead of pictures. Please view only if you have a strong stomach. This is what i have observed:

1) The sick eels were always "standing up" and trying to poke their nose out of the water

2) one of them was shitting stringy white poo

3) every dead eel had a super swollen anus

4) the last eel has white egg-like things sticking out the anus

http://i958.photobucket.com/albums/ae65/jerrychuayw/Mobile%20Uploads/DSC_2090_zpsz9iu8zhg.jpg

http://i958.photobucket.com/albums/ae65/jerrychuayw/Mobile%20Uploads/DSC_2095_zpsjjvdrviw.jpg

http://i958.photobucket.com/albums/ae65/jerrychuayw/Mobile%20Uploads/DSC_2104_zpsww3mqiui.jpg

So I'm hoping for some advice. Does any expert here know what happened?? I have no idea whether it was bacteria, or parasites or something. Water parameters seemed to be ok. I only fed them live glass shrimp ONCE in order to get them to eat before i trained them to eat frozen food. Unless I'm super unlucky, parasites seem unlikely. L

Lastly, what should I do with my last moray? He seems ok so far, contemplating whether i should just acclimatise him straight to marine and hope whatever bacteria present will be killed by the high salinity, or should i dose him with medication just in case? Haizzz

[inwear]

I happenes to see these "freshwater" eels selling for $4 (pre-bagged) at one of the shop at c328 2 weeks ago. Haizzz

[acidjc]

Hi TS is your tank properly cycled?

New tank water cloudy is bacteria outbreak, this could happen to old tank as well if you change too much water or media at once.

If bacteria outbreak just change 20-30% water will do, add an air stone inside, it should b clear in the next few day, if u keep wc, the outbreak will last longer. Also too wc will affect and stress the fish even more.

Sent from my D2533 using Tapatalk

[kenyee]

Hi TS is your tank properly cycled?

New tank water cloudy is bacteria outbreak, this could happen to old tank as well if you change too much water or media at once.

If bacteria outbreak just change 20-30% water will do, add an air stone inside, it should b clear in the next few day, if u keep wc, the outbreak will last longer. Also too wc will affect and stress the fish even more.

Sent from my D2533 using Tapatalk

Hi, may i ask how much is much for wc to cause such bacteria outbreak?

I have noticed several times after my 40-50% wc, my fishes tend to scratch..after a week or so, no or lesser scratching..sometime this make me ponder shd I dun wc or wc lesser..

[acidjc]

Normally wc 10-20% enough. Unless your bioload is high.

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[tuajia]

Hi TS is your tank properly cycled?

New tank water cloudy is bacteria outbreak, this could happen to old tank as well if you change too much water or media at once.

If bacteria outbreak just change 20-30% water will do, add an air stone inside, it should b clear in the next few day, if u keep wc, the outbreak will last longer. Also too wc will affect and stress the fish even more.

Sent from my D2533 using Tapatalk

Hi bro, yes my tank was actually 4 months mature before I even added my eels. I also do 10-20% WC every week. In total my tank was running for about 8 months before the disaster happened. That's why I'm so confused

PS: Wait, I remember now... I only tested the water AFTER I did the WC... I was panicking so I didn't think carefully. After the WC, parameters were fine. It could be possible that the parameters were bad before the first WC. No way to confirm that suspicion now, though. Damn... maybe my daily WC actually worsened the situation. I feel guilty now.

[illumnae]

If white shit and swollen anus likely to be internal parasites, though that doesn't explain the cloudy wate (unless they were thrashing about the sand due to discomfort and stirred up debris). Alternatively, are you certain your eels can do well long term in brackish water? It could be long term side effects of hyposalinity on the eels?

[tuajia]

If white shit and swollen anus likely to be internal parasites, though that doesn't explain the cloudy wate (unless they were thrashing about the sand due to discomfort and stirred up debris). Alternatively, are you certain your eels can do well long term in brackish water? It could be long term side effects of hyposalinity on the eels?

Hi bro, according to my research, Gymnothorax Tile and Gymnothorax Polyuranodon are supposed to be brackish, though they can be acclimatized to marine. In fact, they were being sold as freshwater at the LFS. The only real marine one was my fimbriated moray, who sadly passed away just today, before i fully converted him to marine (he was also sold as freshwater)

No more eels left. I also decomm'd the whole tank and washed it just to be sure there's no more of whatever killed them. Now to take a break and wonder what to do with the tank... Haizzz