When you find yourself trying to remember a show (or any works) that's on the tip of your tongue but just out of reach, come here - the collective brain of the TVTropes community can probably help. Post all the details you can remember (examples help). If you're looking for a trope, head over to Trope Finder. Have general questions about tropes? Visit Ask The Tropers!
Please guys, this thing is bugging me since I was six
Based on your description, I found an Anime made by Nippon Animation, the people behind Future Boy Conan. It's called "Blocker Gundan 4 Machine Blaster", in Italy it's known as "Astrorobot Contatto Ypsilon". The protagonists are 4 Mech Pilots who fight against an invasion. It's also pretty old, I'm speaking of the 70s.
I'm sorry, but it's not the one. If it was not for the creatures I saw (the charred men were quite creepy) it could have been even a non-serious anime: the boy had the classic "Opaque Nerd Glasses" complete with spiraling lines and his mech was literally a metal fish (like a big metal carp). In the episode that I saw they fought against against a giant tentacle monster inside a tunnel: it was pale, with smooth tentacles that crawled and whipped at an impressive speed and with some discoidal central body that the younger girl (a chubby short girl that lost a tooth during the fight) tried to attack with her bug-like mecha (another funny-looking mecha, it was roundish, with two eyes and two pick-shaped frontal appendages). This anime must have had some notoriety, otherwise none couldn't have been bothered to translate it in Italian.
I found it! It was "Gowappa 5 Godam"!
Edited by CritterMaster
Hi guys, could you please help me with this one? Twenty years ago I watched an episode of a strange anime: the protagonists were four mech pilots, two boys (one of them was a short boy with thick glasses and manned a fish-like mech) and two girls (one of them was a little girl that manned a scarab-like mech), and there was some race of humanoids that in Italian were called "Signori degli Abissi" -it means "lords of the abyss"- (in the episode that I saw they looked like featureless charred humanoids, which for some reasons turned to dust starting from their head). It had the graphics of Future Boy Conan. Thanks in advance!