they both seem to be weighted ( like a magnet) to the bottom. If I feed they swim like mad to the top to get food but then after a minute or so hover back to bottom and "plop" back to the bottom. If they don't swim for a bit they lay/fall onto their sides and I've often mistaken them for dead.... Before they flutter up slightly when they see me.
I've done 2-3 five gallon water changes over the past week . Water salinity is 1.023.
Sorry to be so long winded and glass is dirty but don't wanna stress any more than have to. Any ideas of what may help?