Meds needed on hand for Clown loaches

[infer66]

Last week I have placed 7 Clown loaches in a 125 US gallon tank that was set up for them three months ago. 6 of them are 12-15cm, and 1 is 6cm. I also have 5 Swordtail and 6 lyretail mollies.
Filtered by Eheim 2080 and Rena XP4 a 24w UVS in line. Temp is 80 degrees. Water quality is ok. Ammonia 0, Nitrites 0, Nitrates 10-20, PH 7.6. 20% weekly water changes. Pool filter sand, Anubias, and driftwood.

I am treating them with Protozin for a mild case of ICK, they seem to respond well to it.

Three of them seem to be very underweight even though I feed them a variety of food. I placed an order for Wormer Plus and I am waiting for it to arrive.

My question is what other medication will I need to keep on hand for future emergencies and in case Wormer Plus fails to treat them. My LFS only carries Protozin, Sterazin and Octozin. Keep in mind I am located in Europe.

Thanks

[Diana]

I would not keep meds on hand, in case they expire before I need them.
When I see an issue that might turn into a need for medication I do a couple of things that can work without meds, and are good for a few days until the stores open up again. However, the stores are never closed so long that the tanks need to go more than 24 hours without medicine, and I can usually find what I want pretty fast. There are several good stores in this area.

Water change with gravel vac, clean filter.
Add activated carbon, Amquel Plus.
Ultra Violet Sterilizer. I have 2, one for smaller tanks, one for medium tanks. If the big tanks needed it I would have to use both together.
Salt. (Sodium Chloride) Kills all sorts of bacterial and parasite issues, and helps with stress.
Epsom salt for constipation or to help raise the TDS to reduce stress.

Meds I do have on hand with long expiration dates:

Melafix and Pimafix. Not for use on Anabantoids, Loaches and primitive fish such as Polypterides. (That describes about half my tanks: Loaches, Gouramis, Bichers...) This material does not get a lot of use.

Medicated food for intestinal parasites. I got the pond size jar, and still have quite a bit.
Same, for bacterial infections. (Then the fish never got sick. I think it has passed the expiration date)

Left-overs, already opened, probably expired:
Rid Ich, several algae control chemicals (I do not use them. Got them with used tanks I bought.)

If the meds were harder to find (Not stocked, or stores closed longer or more often) I would make sure I had an Ich remedy, and antibiotic such as Kanamycin that covers most of the more common fish diseases. I would not bother with meds for internal parasites, this sort of problem is not such an emergency that you need the meds right now. A few days is no problem. But I would still depend on water changes, UV and salt as a first action.