A little while ago I lost all my peas.
I had 5 in my 4' 75 gallon tank, i added 5 more thinking it was heavily planted enough to provide more territories. There was the initial re-establishment of the pecking order, but i made a huge mistake.
In all my tanks i use remineralized RO so i thought it would be a good idea to set up a reservoir to store up to 30 gallons of RO that way i wouldnt have to wait 30-45 minutes for a 5gallon bucket to fill. I unfortunately have a very poor sense of smell and couldnt tell there was a bacteria bloom in the RO. After a water change with the contaminated water the peas all got fin rot from nipping to establish the new hierarchy. I didnt notice where the bacteria cam from until the next week when i opened the reservoir for my water changes and the smell was "loud" enough for my near useless nostrils to recognise.
I realized immediately why they were hiding and looking less healthy. I did a massive 40 gallon water change (not from the contaminated source obviously) and I tried to catch them to set up a hospital tank but they would all immediately hide when the net entered the water. I couldnt get any of them out.
I now have one solitary pea who i see once every couple of weeks probably surviving on baby neo caridina and amano larva. Hes always fat when i see him and it breaks my heart every time he comes out knowing i failed them and was helpless to save them.
I dont think i will try peas again for a while, but thankyou to everyone here who helped and educated me from a solo pea in a 5 gallon to my once happy shoal of 5.