Slimy Water

Question
My fish tank has crystal clear water, but every time I put a hand into the tank, my hand becomes covered with invisible slime. The slime also grows on the tank sides and the filter and heater. Is it a type of algae?If so, what kinds of algae eaters will eat it?

Answer
Hello Antony,

What appears to be crystal clear water is not.  You have a form of Cyanobacteria (Slime Bacteria) which isn't the maroon variety.  It comes from overfeeding and dirty water, and sometimes from tap water and phosphates (sometimes from detergents and dechlorinators or cloudy water removers).  Phosphates are used as a "De-clouder" for most water clarifying products.  They only adhere the particles together and then it's filtered out, hence, the water gets clearer in our eyes, but it's still very dirty.

Now, for your aquarium, which appears to have crystal clear water to have slime bacteria, it is indeed having an issue somewhere.  Water quality isn't diagnosed by the appearance of the water and it's not a good indicator of clean water. :)

My advice is change out 25% of the water today.  Wash all the filtration thoroughly.  Make sure you have sufficient filtration (Ie: If it sells as a 30 to 60 gallon filter, assume it's the 30 and add another), and if you are using a water clarifier product, stop.  It is the cause.  This invisible slime is potentially harmful to fish.  It's a bacteria.

Good luck and happy holidays.  Feel free to followup with another question if you need to.

Renee