I have had african cichlids before, but took a long break. I bought 11 african cichlids and a plecostomus on December 31. Everything was going fine. They're in a 29gl tank with a whisper filter, aerator, and heater, it has a hood with LED lights on it. All levels were good, except for last night the ph dropped from 8 down to 7.2. Tank temp has been good too. I noticed first that Physics wasn't looking great. Some of them didn't seem interested in dinner yesterday. Moonshadow started thrashing through the tank, crashing into rocks and decor, and within a short time Moonshadow died. A little bit later Physics started doing the same thing. A while later Physics died. All the other fish seemed to be fine. I stayed up for a while keeping an eye on the tank. While I was doing that I slowly worked on getting ph up as to try not to shock them. I had to lay down to try to get some sleep (just after 1:30am), and I woke up at 5:30am to 5 more dead. Snickers in the filter, Blue under a rock, powder under another rock, Fireball was on the bottom toward the back, and Abyss toward the front. I only have Plechy (plecostomus), Lennon, Starburst, Quantum, and Pina Colada left. A couple of them aren't looking the best either. I'm heartsick, and I feel so frustrated and helpless. I'm on well water, I treated the tank with the water treatment stuff, temp is good, all levels are good except for ph had a drop, they had places to hide. I did clean the tank yesterday, but only took out about 15% of the water. When I refill the tank I don't put in water that's too hot/cold so I keep the temp around the same. When I pour it in I use my hand as a "buffer" so it's not causing a huge current or scaring the fish. I try to be really quick in there too. I don't spray chemicals in the air that could fall into the tank. I have run through every possible thing I could, and I don't get it. They don't have any specks, no white poop, etc. The only thing I noticed was that some of them looked stressed. My blue ones with black stripes looked darker than normal. This literally happened within the day (really, just hours). Other than PH the only thing I can come up with is either bloat, or dropsy. But I'm not really sure. Unless it's because my son's father put a few (recently) dead crickets in the tank and they ate them and maybe something was wrong with the crickets? The crickets were bought for my son's Gecko Charlotte. I only have 4 of the 11 left, and I really want to try to save them if I can. It's not even just about the big financial hit for me, we are attached to these fish. I took a few videos shortly before Moonshadow died. I'm only uploading 1 right now because they take a long time to upload, but I do have a few more if you need to see them. It's pretty much all the same though, the only thing I see aside from the thrashing is going sort of floppy/belly up. Most were Malawi, and I have read it's pretty a pretty common issue for them to get bloat, but they didn't look bloated (though I read they don't have to look bloated to get bloat either). The tank never had fish in it before this. I bought it new, washed it out as directed, filled it, and treated with water treatment. I let it cycle for a little while before putting the fish into the tank. I've covered everything I can think of right now to cover. It really just came out of nowhere. There were no signs of sickness, sluggishness, or odd behavior before last night.