Well, beginner aquarium keepers or experts, let's admit it - we all had that regrettable mistake in one point in our lives.
Let's all be curious and admit our past mistakes. I guess what's important is we do something about it
Besides, this could also help other aquarist so they could avoid the mistake
So uhm, I guess I'll start?
6 years ago, I had my first aquarium (20 gallon). And I stocked it with:
2 goldfish (very wrong, great poopers need greater tanks)
1 common pleco (uhm, admit it, you once did too!)
2 pangasius cat (too large long-term for that tank)
2 red swordtails (nipped the goldfish in its entire life)
but placed in direct sunlight. So (wait for it) algae bloom! (the LFS
told me to place it there so the goldfish would retain its color)
It was murder.forgive me
Now, it is happily stocked with danios and ghost shrimps
So uhm, how about you?