I have kept various fish in my different size tanks for about 26 years now. I got my first clown loach about 9 years ago and that guy lived in the tank for some 6 years. This species is highly succeptible to Ich and fungal infections. I didn't notice mine getting sick in time, and he was dead within less than 24 hours. Probably the best thing to do is to up the temperature of your tank, if you suspect Ich. Because I have freshwater clams and Atya gabonensis filter shrimp in my Botia tank, I cannot use copper-based medications. To those of you who have inverts in the tank, try MelaFix. I did and it works. It smells good, too.
Clown loaches are the best choice for inexperienced loach fans. They will survive in water as warm as 30°C and as cold as 16°C. They can adapt to a pH of 6.6, or a more alkaline pH of up to 7.6. They seem to be able to eat everything from minced krill to spirulina wafers to live preparations, such as daphnia, bloodworms and black worms. Clowns tend to rest on their sides, looking nice and dead: don't be fooled by their looks. If this fish were dead, others would probably inspect it. Clowns are best kept in groups as they tend to be extremely sociable. For some 6 years, I had an African Knife and a Clown Loach in a tank. These two were best of friends, the Knife swam with the Loach and the two shared everything, including a good size lava rock cave. I have never witnessed such 'friendship' between any other fish I have ever owned, and believe me, I have owned a few.
A word of caution for snail lovers: if you own snails for tank cleanup, or just for the SG's of it, say goodbye to your invert friends: clown loaches are EXPERT snail eaters; they will eat everyting from little ones to big Cana and Apple snails. This may be a good thing if your tank is infested with snails, however, no snail is safe.
I love my trio of clowns! They each exhibit individual personalities and intelligence. I have large gravel as a substrate and if a food pellet falls underneath I have observed my clowns picking up the pebbles in their mouth and moving them out of the way until they dig down to the food. Amazing! They are somewhat susceptible to Ich and when I introduce new fish I treat the tank with Aquarisol (without raising the temperature) for three days as a preventive measure. The first clowns I owned got Ich and Coppersafe did nothing except weaken them until they died. When you first buy clowns they are easily stressed and very shy. I've found that the best thing you can do for them is to provide some sort of cave or hiding place. Also remeber that these fish grow up to around a foot in the wild and need a large aquarium to be happy. Clowns eat about anything, making clicking noises as they gobble up flakes, worms, zucchini, and pellets. New plants cause a snail outbreak? Don't worry, snails are their specialty.
Just a note to owners of clown loaches and other non-scaled fish (and invertebrates). Clown loaches (and other non-scaled fish) tend to become infested by Ich more readily. A definite no-no to cure this in a tank with these types of fish and inverts is to use any cure that contains copper. Copper is often detrimental to these more delicate fishes that lack scales and inverts, this goes for marine as well. So just be careful, and read the ingredients on all supplements and medicines carefully!
Clown Loaches are one of the most inquistive and intelligent fish I have had the pleasure of owning. I rearrange my tank every month or so, so they can be in an interesting environment. After I am done they will immediately come out of hiding and systematically explore the tank. I think they recognize some of the pieces of slate and wood by smell! I have rearranged one of their favorite caves made with driftwood and have seen them circling and smelling it in its new location. As if to say 'this doen't belong here'. I have also seen my loach engage in a tactical battle with my male German Ram who was trying to seek out a territory in the tank. I have seen my clown loach hover under the lip of a large rock at the boundary of the territory and spring up suddenly to chase to Ram. The loach was thoroughly enjoying himself but the Ram was wasn't! Very fun for your tank and well worth the investment. They will get bored and lonely if not kept together. (Beware: when bored they will make up their own fun!)
I have kept many aquariums over several years, but none without the beauty and elegance (and craziness) of clown loaches. I have three clown loaches in my current tank, and when they are not digging through the gravel foraging for leftover food or resting wherever they please, they are finding some other way to make me laugh or marvel at their actions. There is one specific loach that is my favorite. I was planting some new plants into the substrate one day and to do that, I turned off my powerhead. Just as I had finished, I saw my clown loach enter the powerhead and rest inside. To this day, I have never found out quite where (or how) he rests, but since that day my powerhead has been turned off to serve as my loach's favorite resting spot. I wouldn't get rid of him for the world.
After having a planted tank for some time, I recently started introducing fish to it: 6 Cardinals, 2 Angels and 2 Clown Loaches. These guys could not have been named better... they exhibit some very odd behaviour, and I'm quite sure the other fish are confused by their actions. They constantly engage in a dual dipping action where one of them starts at the top of the tank, and the second at the bottom and they exchange places through very deft swimming, so fast sometimes I think that they are going to bang into canopy. This morning I got up to go to work and went to feed the fish. No clown loaches!! After some investigation, I looked at a few plants I am trying to root, that I have kept in their small rooting pots. There were the loaches completely vertical, face down, tails in the air (er.. water?), with absolutely no motion, not even breathing that I could detect. As other readers have said, I promptly got the net to remove their bodies from the tank when BAM! They spring to life ripping up everything in the tank in panic, kinda like when I get woken up from a sound sleep :)