Help. I have no idea what happened to my loach. I’ve had them for 5 years no issues. I have also noticed another one swimming erratically.
Those red spots on the body suggest it is very likely bacterial infection. I forget the name of it but it kills in 24 to 72 hours. I tried to find the name but can't recall. Did you recently add a new fish to your tank ?
It looks like the loach is exhibiting hemorrhaging Septicemia. Most likely some variety of bacterial infection.
Check your water parameters to make sure the loach isn't the victI'm of an ammonia spike.
Not much to be done in the way of treatment other than a 50% WC and concentrating on keeping the tank clean. Chances for recovery are slim.
Unless its a particularly virulent strain of Columnaris, the bacteria is spread by tank mates consuming a dead infected fish.
The longer an infected fish is allowed to incubate the bacteria in its body the more virulent the strain becomes.
Its best to remove the infected fish asap and either treat the disease w/ antibiotics in a QT tank or euthanize.