Can I keep all of these fish in my new 250L tank

June FOTM Photo Contest Starts Now! Fish of the Month
🏆 Click to enter! 🏆

Hard water is water which has a lot of calcium and magnesium dissolved in it. Soft water fish have evolved to hang on to the bit of calcium etc in the water. Put them in hard water and their bodies continue to hang on to these minerals, and they can develop calcium deposits in their kidneys as they have not evolved to process this much calcium. This shortens their lives.

Most shops have no idea about the effect of hardness on fish, and most people who start keeping fish have no idea either as the shops can't tell them. We have a member who thought that his fish living 18 months was a good long life. Until he started using RO water instead of hard tap water and the same species are now going strong at 5+ years.

Most reactions