Anubias plants turning yellow with black dots and holes

[Lexat]

Thanks for the heads up flamex. I had a look at the rhizomes when I did the water change and they seem to be in good health, firm to the touch.

[Lexat]

I think it's crucial we understand what nutrients or fertilizers are currently being used. While light can be a factor, particularly for shade plants like Anubias, I don't believe that's the issue here.

Adding a single nutrient, such as iron or potassium, is rarely beneficial and can often cause more harm to plants, and even fish. Plants require a balanced mix of 17 nutrients, which comprehensive fertilizers are best at providing. Fish, fish food, and water changes do provide some nutrients, but they may not be enough.

I've had a bad experience with iron myself - I once added extra iron to my tank, as someone advised me to, and it ended up killing my floating plants. Iron is a micro-nutrient that's best left in balance with other nutrients in a good quality comprehensive fertilizer. Excess iron can also lead to algae problems. Potassium, on the other hand, is relatively harmless, but it's unlikely to make a significant difference if other nutrients are lacking.

Meant to say boomer, I'm actually using the Flourish Comprehensive Supplement.