Mysterious clown loach deaths

[Bitey]

I ordered 20 small (~1.25" long) clown loaches from liveaquaria.com last week. They shipped Thursday and arrived 9 am the next day with no losses. I trickled water into a bucket containing the fish and their original water over several hours until the TDS of both the tank and their bucket water essentially matched.

The tank is several years old with a 40 gal with a Filstar XP3 and a 25W UV sterilizer. The filter has one tray of sponges and two trays of biological media. I removed the gravel 3 weeks ago because grew tired of vacuuming gravel. Two baby Oscars previously inhabited the tank and then were moved to the main tank after their quarantine period ended.

I fed them generously Fri-Sun.

On Sunday, I found one of the healthier-looking loaches dead.

On Monday, I found another dead and changed out most of the water. Another developed equilibrium problems and was lethargic. The lethargy went away after the water change but his equilibrium problems remain.

Tuesday, I only fed a slice of zucchini and cleaned the filter. The filter wasn't particularly dirty. I took care not to expose the media to tap water.

This morning, I fed them 8 of those small Hikari sinking carnivore pellets. Afterwards, I noticed one loach was laying on the bottom breathing rapidly and died shortly later. Strangely, all the loaches (except the one) seemed healthy. The dead loaches appeared to have full bellies so they were apparently behaving normally until close to the time of death. The one that died today appears abnormally plump. Those previous two seemed to have dark gills but not this one.

Another 95% water change is in progress now. As always, the replacement water is RO water trickled in over several hours with a full dose of Prime in case anything toxic gets past the RO filter. The RO filter's cartridges are changed every 6 months and the water used on Monday were filtered with cartridges nearing replacement. New micron pre-filter and carbon cartridges were installed Tuesday.

pH ~6.5
Temp 82-84F
nitrate not tested
nitrite not detected
ammonia not detected

I tested nitrite with a Lamotte test kit with expired reagents. I went to a local Pet Smart and bought an Aquarium Pharmaceuticals test kit as well.

I thought I had Seachem and Lamotte ammonia test kits but can't find them. I did find a Seachem ammonia alert that is several years old but had never been used. It was a shade darker than the safe color but lightened up after some time in the water. I tested it by removing it from the water and holding it over a bottle of ammonia. It turned quite dark and then returned to normal after being rinsed and soaked in clean water. I did order a Seachem ammonia test which should arrive Saturday.

What confuses me is how fish that appear healthy are suddenly dropping dead while the rest appear to be doing fine. If I could detect an ammonia or nitrite spike it could explain things.

I don't really know what to do now except to continue with large water changes and feed sparingly, if at all.

Well, one thing I might do is put some of them in my 10 gal planted tank. There are only snails there and it's heavily overgrown and badly in need of pruning. I could put a few in that tank and not really feed them any additional. The planted tank shouldn't have any ammonia or nitrite (though I'll test the water) and may be better than seeing the loaches picked off one at a time.

[chefkeith]

I'll shoot with you straight.

It could be that the small clowns didn't travel well. What aquabid seller did you get the clowns from?

I'm curious, what was the TDS of the bag water and the tank water?

If they are dropping dead for no apparent reason, the I'd suspect something in the gills or internally.
I would of treated them for ich and other internal/external diseases as soon as I got them regardless of where I got them from. It doesn't take a full blown infection for them to die. Usually by the time an ich spot is seen, it's too late. I'd worm them with prazipro and levamisole also.


Tell me more about the water changes.

Do you add pure RO water to the tank or do you add something like KENT R/O RIGHT to the RO water 1st?

A 95% water change sounds very extreme to me.
I'd never suggest anything more than a 50% water change unless the fish are conditioned for it.

I hope the clowns get well soon.

[Tinman]

Yes what Keith said, or even little 10 percent water changes spaced throughout the day to accumulate a total change out over several days at most, but not so big at one time. Baby steps

[tariesindanrie]

So sorry to hear about the casualties. I hope everyone else hangs in there!

Keeping good thoughts

Kate

[MTS]

The fish may have gone through some extreme temperature changes also. I'm not sure that either the middle of winter or the middle of summer is a good time to buy mail order fish. Some dealers won't ship in extreme weather conditions.

[Munkee]

I assume they did not ship well, and/or had a parasite that was unknown at the time.

The upside is, if it has not been longer than 14 days, you can contact liveaquaria.com and they will ship a new batch or refund your money. They have a 14 day guarantee on all live orders.

I am sorry to hear about your loss.

[Batch]

Hey,
This dosen't answer why you are losing them, but 20 clown loaches
in a 40gal tank? Or is this just the QT tank?
Batch