Hi mate I have 3 in my tank they are filter feeders when they feed like this means not enough food in the water column,so at night when the lights are off crumble to powder some fish flakes and put into tank and you’re see them perch somewhere in the flow/current fanning their arms catching the food 😀
cjsprigg 
Hi mate I have 3 in my tank they are filter feeders when they feed like this means not enough food in the water column,so at night when the lights are off crumble to powder some fish flakes and put into tank and you’re see them perch somewhere in the flow/current fanning their arms catching the food 😀
Looks like he’s sweeping 🧹
I miss mine):