Does anyone know of any aquatic plants that like brackish water? I've heard that Vallisneria and Java Fern can tolerate it.

java moss as well

Brackish water and plants generally don't mix too well. At a low salinity level java fern, java moss and anubias did okay for me, but as I upped the salinity they stopped growing and then died. I believe marimo balls do well. Mangroves would do well in a variety of salt levels, also some sea grass, but they require high light. Try looking into macro algae for the saltier end of BW.

Snail is correct. I have tryed using many typs of ferns & micro alge nothing survived. the only thing I had luck with was a Mangrove. My mangrove is about a year old now.

I had decent luck with vals when the SG was lower than 1.005. When I upped it to 1.008 they all died off, however.

I have 2 banana plants currently doing well. Their growth has slowed a bit, but they are growing none the less.

I got tired of killing plants/wasting money & started incorporating plastics back into my 55 recently.

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-Never put a Chinese Algae Eater in a Guppy tank unless you enjoy vacuuming little corpses out of the substrate.-

55 Gallon/brackish (1.009)-
1 dragon goby
5 black mollies
4 bumblebee gobies
14 ghost shrimp
2 snails of unknown species

20 Gallon/freshwater/planted-
3 zebra danios
2 snail of unknown species

10 Gallon/freshwater-
currently fishless