http://forum.aqua-fish.net/ A forum devoted to aquarium fish, plants, techniques and fish keeping as a whole. en http://forum.aqua-fish.net/?topic=bristlenoses-acting-strangely-#1 Hi! I cleaned my tank and replaced the 2-4 cm black pebble substrate to 2-3 mm light-brown gravel. Ever since I put my bristlenoses back to the tank, they act in a strange way: they keep coming up for air and their fin movements seem nervous. It cannot be lack of oxigen because most of the water is fresh and the air pump is working. What is their problem? Are they in a shock? Please, help! leyton 2011-12-20 http://forum.aqua-fish.net/?topic=bristlenoses-acting-strangely-#2 This could be related to temperature, water chemistry or even bulbs may be emitting too much light towards new substrate which definitely reflexes more light than black pebbles. Hard to tell without knowing more, even pictures haven't been attached. jan 2012-01-18