Does anyone know If pink and green Japanese river rocks are safe?

I wanted to use these in my axolotls tank and have them washed and soaking but wanted to make sure they're safe as they're usually used for ponds and gardens. Couldn't find much about them when I looked them up.

they say they can be used in fish tanks, but as i an hopeless with sizes i would just make sure your axie can't fit them in its mouth

Thank you, these are a lot bigger than axolotl. Was worried in case colour of rocks could leech into water but since I've soaked them I haven't seen water colour change.

If they are safe for ponds I can't figure a reason they wouldn't be safe for tanks, barring the mouth size as gwnm indicated. As far as I know, rocks are rocks, and if they are clean, I wouldn't hesitate. I've brought back rocks from all over creation in my time and never had a problem using them in tanks. Except for that time I put some radioactive uranium in one of my tanks and after a few months the newt sprouted wings and flew away.

Sorry for the delay, but there is a GREAT way to check! If you have a API nitrate test kit, put a drop of solution 1 onto the rock; if it fizzes the rock is unsafe. If you DONT have the test kit, you can try vinegar, though it is a much weaker acid and thus not as reliable.

Here is a basic list posted previously:

Safe Rocks:
Crystalline Quartz ( also known as Rock Crystal, Amethyst, Citrine, Rose Quartz, Smokey Quartz)
Granite (care must be taken with granite, some forms contain high concentrations of pyrite)
Jade
Microcrystalline Quartz, also known as Quartzite and its metamorphic forms: Jasper, Agate, Chalcedony, Sard, Carnelian; Green coloration should be avoided due to presence of copper)
Onyx
Petrified Wood
Slate
Basalt
Porphyry
Schist
Commercially available “River Rocks”
Mica
Tapecrete or similar acrylic based concrete products, properly treated and sealed
Obsidian

Unsafe Rocks:
Coal, as a naturally occurring hydrocarbon, this rock is often contaminated with many other hydrocarbons.
Lava Rock, not recommended due to a multitude of sharp edges and the possibility of high sulfur and hydrocarbon concentrations
Coral, causes alkalinity issues
Dolomite, the metamorphic form of limestone
Fools Gold also known as pyrite (or any other rock with metallic veins--Acid Producing and even more so, often a lead hazard)
Any rock with a green or greenish color to it, these are most commonly contain copper)
Fossils, with exception to those in Slate
Limestone, the sedementary form of coral
Manufactured Quarts Crystals
Marble, if not sealed with a high quality aquarium safe epoxy
Sandstone
Shale as it often contains hydrocarbons that can be harmful in a captive enclosure
All Metamorphic and Sedimentary Rock not on the safe list

Thank you, I will try that in future.