fish health

Hey y'all! There has been a few threads on here about QT tanks or at least related to them, and it got me thinking. What is the (is there a) recommended size for a regular QT tank? I see and hear about some people using 5,10,20 gallon tanks for QT, but there actual tank size is 5 or 10 times...

Okay, so heres the problem. I got my little Niger Trigger (1.5") just under a week ago. Fairly new addition and tends to hide in his corner half the time, and the other half he swims around up to about the mid point in the tank. Since day one he has eaten masses, been happy to not just hide and...

so i bought a sand-sifting goby about 2 months ago, he was doing quite well in my tank but recently he has looked very skinny. i dont know if this is because he isnt getting enough to eat in my set up or what. i turned on the lights a few days back and now i cannot find him... ive heard of these...

so i did a 25% water change yesterday on my 40g breeder. i ran a test before the water change and after and everything was pretty much the same except for the alkalinity which is usually around 10.2dkh went up to 12.2dkh. my nitrite and ammonia is always 0, ph has been 8-8.2, phosphates is...

Just an observation: There are so many problems or concerns in this hobby about fish diseases. I really don't know why so many people have problems with this but I have a hunch. Our fish in the sea never really die of old age. A fish, unfortunately, is an animal that usually ends it's life as...

so i have a newly established reeftank which is in it's 6th week. i've had a cc starfish along with some hermit crabs and snails and i just added a featherduster and some mushroom polyps. however, i keep getting all this brown stuff on my sandbed and walls (i mix the bed up and wipe it off but...