Snowflake Eel and Several Other Fish Gone

[mav.23]

Hello everyone! This year I am taking Marine 2 honors, and one of our projects is to design a marine tank and make observations, and learn how to test water, etc. So we decided on an aggressive tank, and we bought a juvenile snowflake eel, a young clownfish, a damsel (who is pretty chill for a damsel) four chromis (we read they do best in groups), a scissortail dartfish, and a green gobi. First, one of the chromis went missing. We later found his body in the filter. Then, the gobi and the scissortail vanish. We search everywhere, and they are just gone. No bones, no remains, no nothing. Then two more chromis are gone, and finally, the eel is missing. Our lid wasn't on very well, but we checked the whole room and took everything out and it didn't jump. I haven't seen it for maybe two days. Our teacher, who was working as a marine biologist for several years in the Caribbean told our group that the eel wasn't what was killing off all our fish. Now we only have one chromis, a clownfish baby and the damsel. They're all juvenile, except the chromis. We doubt that anything is eating them, because we have been looking everywhere for remains. Nothing is in filter either. Apparently, snowflake eels don't burrow, but even if it did, he/she would have poked it's head up out of the sand to pump the water over it's gills. Does anyone have any advice or suggestions? I have been keeping aquariums since I was young, but I have never had this happen before. If there is any criticism, please keep it constructive

Some details:

We have a 55-gal tank
There is a thin layer of sand/gravel mixed, and then about 1-2 inches of white sand.

Eel is fed brine shrimp and scallops 1-2 times a day, besides weekends, but we leave a little bit of extra food in there on Friday, and all fish but the last two (not counting eel) went missing over the weekend.

All nitrate, nitrite, ammonia, salinity etc. tests all are where they are supposed to be.

Thanks for your help

 

[arielw]

Any possibility you have an unwanted hitchhiker in tank? Maybe a very large worm or mantis shrimp. Best way to tell would be to put a dim light/blue night light on tank at night and observe or film. I agree a small snowflake should not be the culprit.

 

[Cliving1]

So first you lose a chromis, which regularly reduce their ranks to 1. Did you notice any red marks on them? They are highly succeptible to uronema. What kind of goby did you have? Both goby and scissortail could be hiding depending on tank size and rockwork/amount. If you have a good cleaup crew and they did die, they likely took care of the remains. 2 more chromis gone, so now down to 1, possibly chromis were picking eachother off. I agree with the teacher, reason being, if the eel ate the fish he would have eaten them, not left bodies lile in the first case. What size eel is it? Snowflakes dont burrow but will lay in the sand and rockwork and will vibrate to make room for their body. I would suggest looking around the tank again. If the lid was loose, you could have lost all fish to jumping. Ask the janitor if they saw anything. Hope this helps.

 

[mav.23]

Thank you! I have that class tomorrow so we will try that!

 

[mav.23]

And also, it was a small, maybe 4-5 inch eel, and very skinny. Janitors don't come into that room, and there were no bodies on the ground. We considered that the chromis were picking each other off, and the goby was a pretty chubby green one. I don't know where he was hiding. I heard eels can hide, so I'm hoping he is only coming out during the night though. Scissortail is very small and could be hiding somewhere. Thank you both for your help!