Sounds to me that your set up is far from ideal for elephantnose however you could argue mine is also not right in an overstocked tank with 6 giant featherfin cats and 30 voracious congo tetras for competition (not to mention the knife fish, mbu puffer and 3 large ctenopoma) but on the contary to what everyone else says these fish are tough little buggers from my experience. ive had mine for 4 years and he is the most boistrous and agressive fish I have, he outright bullies any fish bigger that him, chasing and bashing the big catfish. To ensure he gets enough food i overfeed like mad feeding huge amount of bloodworm every 2 days. (he will not eat anything other than bloodworm) defrosting in a cup of water then useing a turkey baster to squirt em into the tank.
With his relentless bullying he has come off quite bad with some quite scary looking injuries (which he undoubtly deserved, he really is a terror!), chunks of flesh and skin hangin off him but he heals up and looks as good as new in a day! I just wish he left my cats alone, the elephant nose is the only one that disrupts an otherwise peaceful tank. When i get my 10ft tank I will have 10 or so elephantnoses in there and hopefully they will just keep themselves to themselves and leave the syno cats alone! With 2 elephantnoses i can imagine one harrassing the other to death, they really are that badly behaved in that respect.
My maintenence routine is basic, 1/4 waterchange a week or 1/2 a fortnight and a filter clean twice a year if that! It has been no harder to keep than any other fish i have kept, just gotta get the diet right!
For the first year i barely saw the little guy, now he rushes up and down the tank trying to get my attention regardless of the light being on, he is the boss of that tank and the other fish sure know it! I have him in a 540ltr aquarium.
Hope this helps get an idea of what its like to keep these little monsters!
edit: I feed my tank around 1kilo of bloodworm a month thats 15 or so feedings from a slab of bloodworm, overkill maybe but i think it may be the key to my successful elephantnose keeping!
If your interested you can see my elephantnose here (he blends into the shadows well tho!)....
http/www.youtube.com/watch?v=WsU-xDYBqSc