In advance let me apologize for how long this post is going to be. Hi, i recently bought a 55 gallon tank off of craigslist that came with: 8 inch Midas/Blood Parrot mix 5 inch Black Convict 10 inch Jack Dempsey 5 inch Jack Dempsey 13 inch Pleco 10 inch Pleco 6 inch Chinese Algae Eater Canaster Filter HOB Filter Under Gravel Filter Hood/Light Heaters Automatic Feeder I've had this tank for about a week, and my water parameters are: 0ppm ammonia 0ppm nitrite 10 ppm nitrate 7.6 pH 78 degrees Fahrenheit I know, this tank is VERY overstocked, but he listed all of the things above and was only asking $150 for it, and I couldn't walk away from the offer. This is my first time owning Cichlids, and right off the bat I can tell that their behavior is a little too aggressive. First off let's start with the Plecos. There's nothing wrong with them that I can see. Their behavior is normal, and they get along with all of the fish. The Chinese Algae Eater is normal as well, all of the fish get along with him and he doesn't harass any other fish either. I'm a little worried about him though, because I've read when they mature they can become very territorial and aggressive; the last thing I need is another territorial dispute in my already overcrowded tank. Now, onto the Cichlids. The 4 Cichlids are in a bit of a territorial dispute. The Midas and Convict are a team against the two JDs. The Midas/Convict's territory is the back left corner of the tank behind a pot decoration, and the JDs' territory is in the center of the tank, inside a large decoration. (Keep in mind that the JDs could be a mating pair, but I am not completely sure yet. I would post a picture of them, but at the moment they are inside the decoration, so it wouldn't be a clear picture. I will post one ASAP) The only time the JDs come out of the decoration is to either a) eat or b) harass the Midas/Convict Whenever the JDs go over to the M/C's territory, its a head to head "stare off". The larger JD is more up in their face while the smaller one is by his/her side, but not as confrontational. The M/C pair do the same, the Midas is trying to shoo off the larger JD while the Convict is trying to shoo off the smaller JD. This doesn't go on for very long mind you, only for about 2 minutes max. This doesn't happen very frequently either because the JDs are very shy and stay in their decoration most of the day. However, when it is night time, the larger JD is VERY active. During the weekends when I'm still awake at 2am, I'd go downstairs to check on them, and the JD is always sitting directly in the back left corner with the Midas and Convict. It's very strange. During the day they seem to hate each other and stand their ground on their territory, but when it's night time and the JDs are more active, they'll just sit together and not do much. My mother comes home from her job at around 2am as well, and she says she sees the same thing on week days when I'm sleeping. So what I'm trying to say is, the M/C pair and the JD pair are very aggressive towards one another, but for some reason they swim among each other during the night like best friends. Questions: What should I do in terms of this aggression and how can I stop it? I was thinking about leaving all of them in the tank for a month since I've only had them for a week, and see if their behavior gets better. Which fish should I remove? I'm planning to remove the 13 inch pleco as well as the Chinese Algae Eater. For now let's assume that the JDs are a mating pair. IF I removed one of the JDs, how would the remaining one react? Do you think he'd get more aggressive or less? Would it be okay to re-do all of the aquarium decorations? I really hate how the tank looks. I was planning to replace all the decorations in a month or two and completely change the way the tank looks. If I did this, would this stress any of the fish? Especially the JDs. Since they've picked their territory in that decoration, what do you think would happen if I removed it? Would they just find a new territory, or what? Thanks so much for reading, I really appreciate it. I'm sorry for how long this is. I think we should have a specific section in Fishlore just for me since I type so much P.S if any moderator comes across this, can you please move this to the Cichlid section, I meant to post it there and now I don't know how to move it.