Dying kuhli loach

[shellyx]

Hi I bought some kuhli loach 3 mth ago and since Monday I've been loosing them.
They don't look ill, just start twisting then die. All my other fish and inverts are ok.
29 gallon tank
Ammonia 0
Nitrite 0
Nitrate 5
Ph 7
Did a large pwc yesterday.
Tanks been running for 12 years
Any help would be appreciated
First time keeping them.

 

[V227]

Sometimes tankmates eat more than their fair share of food. Not enough food reaches the substrate, resulting in starvation for Loaches.

Another possibility is Flukes. It wouldn't hurt to dose the tank with Prazipro.

 

[Andy Sager]

Khuli Loaches can be tough. Because they are more a nocturnal feeder, they often don't get enough food so starvation is a real problem with them. Another suspect is the partial water change you did. It may have altered your chemistry too much for their liking. If you are losing all of them relatively close together, that is the more likely reason. With some fish, it's better to do small water changes daily vs larger ones less often. It reduces the amount of changes happening and keeps the water fresh so nothing can get too high or low.

 

[shellyx]

Khuli Loaches can be tough. Because they are more a nocturnal feeder, they often don't get enough food so starvation is a real problem with them. Another suspect is the partial water change you did. It may have altered your chemistry too much for their liking. If you are losing all of them relatively close together, that is the more likely reason. With some fish, it's better to do small water changes daily vs larger ones less often. It reduces the amount of changes happening and keeps the water fresh so nothing can get too high or low.

I don't think they've been starved i feed repashy after lights out and watched them eat.
Definitely agree it's something to do with my pwc change on Sunday it was after then they started dying.
Someone told me to do a large change and I did yesterday.
Really upset about this, they are one of my favourite fish.
Thank you

 

[Andy Sager]

I don't think they've been starved i feed repashy after lights out and watched them eat.
Definitely agree it's something to do with my pwc change on Sunday it was after then they started dying.
Someone told me to do a large change and I did yesterday.
Really upset about this, they are one of my favourite fish.
Thank you

Sadly, not every fish specie can handle large volume changes. With some species, large volume changes are mandatory for their health but I've not found any loach specie that handles them well. I've found more frequent smaller changes, daily if necessary, to be a better way to keep loaches. That and good water flow in the tank.
For what it's worth, if you do small water changes 3-4 times per week from the get go, nothing should get that high that larger volume water changes are necessary. The water parameters will stay pretty constant that way.

 

[shellyx]

Sadly lost them all

 

[shellyx]

Here's a pic of my last one

 

[Andy Sager]

Here's a pic of my last one View attachment 392011

I don't see any disease so I'm guessing it was too drastic a change in the water chemistry. This sadly, is one of the risks in doing large volume water changes. Not all fish can handle them. All fish can handle small volume, more frequent water changes.
If there is a lesson in here, it's that fish like stability. Some species can handle drastic changes but not all of them do. Your job as a hobbyist is to provide stability.
Sorry for your losses.

 

[shellyx]

Thank you