Pleco dead
My community tank has a problem. It's set at 30c degrees, has a good mixture of fish and plants however I've been steadily losing fish every 2 weeks or so. My red fin shark and guppy were looking a bit iffy last night so I turned the heat up to 30 and this morning I found my plec dead.
Answers:First things first; have you run any type of water tests?
Water tests such as PH and NH (Ammonia) tests should always be your first attempt in determining the cause to any fish death. Since you're experiencing a continual lose of fish, it'd be in your best interest as well as pocketbook to start running tests. Test kits are fairly cheap and easy to use. Most community tanks can run a 7.0-7.4PH level and there should be none to .05 of ammonia.
Next, Pleco's are tropical fish. A good general temperature range is 75-78f/ est.-23c-24c. Be careful with your heater though, other fish such as your guppy prefer a tad bit cooler temp.
Were you feeding the pleco anything other then fish flakes you'd feed to the other fish? Most pleco's won't eat regular flakes, they tend to prefer tabs made especially for bottom feeders or pleco's.
Were there any distinguishing spots or lesions on the pleco that you noted? Like Ich or fungus? How about any of the other fish??
Have you done a water change since your pleco's death? Even if you don't have test kits to prove the water's condition, anytime there's a loss, you should do at least a 25% water change. This removes ammonia that continually accumulates in the aquarium and give your other fish, especially your "iffy" fishies a better chance at survival.