Book about post-apocalyptic survivors and slug-like alien invaders

Question

I read this ~1995-1997, and I think it was new. For whatever reason, my school library had a copy. The story was about the few survivors of post-apocalyptia. Alien slug-like creatures had managed to take over and kill almost everyone. The slugs (silver colored, as I recall) could control their victims, but were sensitive to water and possibly fire. Because of their water sensitivity, most people tended to dwell in the sewers.

We find out that the slugs have been biding their time to invade the sewers and rid the world of the last of humanity. We also learn that all survivors have some form of mental psychosis which prevents the slugs from being able to control them effectively.

I can recall a few scenes:

1. In the beginning, the protagonist is going scrounging through a building and has to defend himself against a wave of the creatures.
2. Among other things, he finds a picture in a frame. He heads to the sewers and trades it for ammo and food, because the picture frame has a thin edge of gold. He and the dealer share a wink at people who still think gold is worth something, which therefore means that they can both profit from the exchange.
3. I think the narrator ends up falling in love with a woman who turns out to be under control.
4. The narrator himself ends up being taken control of by one of the aliens who explains that they have found a way to control people who have psychoses. The narrator responds with something along the lines of "You want crazy? I'LL SHOW YOU CRAZY! HNNNNGGGGHHH" and that actually works.
5. The last of the humans gather to fight against the aliens who have managed to combine masses into one giant creature, rapidly growing armor to protect itself from fire and water. Because flesh wasn't enough to hold the weight, I think they use the Statue of Liberty as a frame to build the flesh around or something. Honestly, at the time it sounded like something from Akira.
6. The good guys win.

And no, this is not Puppet Masters. I remember thinking it was kind of fun shlock at the time. The cover, I can't quite remember. I think it depicted the scene from point 1 above, done all in dark blues/purples/reds.

Answer 1

I think this is The Parasite War by Tim Sullivan. The Amazon description says:

A combat veteran leads a rag-tag group of survivors in an all-out war against invading aliens! The world's cities have been destroyed by a ghastly holocaust from space. The few remaining souls eke out an existence in the ruins, ransacking skyscrapers for food, and living in the city's sewers like vermin.

The cover is dark blue.

An Amazon reviewer complains about:

novel about an alien parasite infection suffers...stating many times how the alien Coloids are destroyed by water yet they feed on humans....inconsistencies continue to mount until the climax at the Statue of Liberty

A quote via Google books:

Alex was wired, his bipolar disorder wildly on the upswing. He couldn't remember when it had felt so good to be out of his mind.

Another one:

Jo took out the picture and handed it to Victor. "Pretty", he said. "More than pretty," Jo replied. "That's real gold."

(in a scene where Victor is a trader they're dealing with)

Finally, although Amazon's paperback (from e-reads.com) is dated 2005, Goodreads says there was a paperback in 1989.