For 4 months I ve been feeding them New Spectrum 1mm size....they loved it. Because they are getting bigger,I changed to 3mm size.They were eating at the start,but have tappered off to...not going near it.I soak the pellets before they enter the tank..as always.I have always changed the water every 10 days...there is a real wooden root in the tank....is this piece of wood possibly leaching.They still go crazy for krill. Thanks for all the advice in advance...Bryan