The proposed species. Clown and yoyo loaches.
However, it would apply to most Botia loaches given that most are comparable to clowns/yoyos in care. Additionally, loaches in general and cichlids can have nonmatching needs that go beyond temperament. I forgot to go over this, but I'll do it now.
The biggest hurdle is diet, many cichlids are largely herbivorous omnivores. Loaches on the other hand, being carnivores, obviously have a dietary conflict.
If fish with opposing diets housed in the same tank eat too much of the other's food, something like this can happen.
The next is environment. Loaches like much more flow than some cichlids, and if they do not get it, the reduced oxygen stemming from reduced flow is detrimental.
Finally, temperature. There can be incompatibilies - such as the below case with the next quote.
Another example would be, say Jack Dempseys with clown loaches. Clown loaches prefer warmer 27 Celsius or so water, while Jack Dempseys are found in cooler water.
Effects of keeping fish in too warm water include a shortened lifespan and getting less oxygen than they need (warm water holds less than cool water).
This is not an advisable combination environmentally, regardless of temperament. Yoyo and zebra loaches prefer much cooler water to severums.
They will not live as long in severum temperatures as they would in cooler temperatures - unless you've had them with the severums for their full 15-20 year lifespan. And severums won't do well in those temperatures.
I haven't, but have spoken to many who have kept both. I can even go and ask them right now if you'd like for their input!
I can't and won't force you to follow this advice, it's entirely up to you. However it's also up to you as to whether or not you want to hear what optimum conditions for your fish are.
