Mr. Saltwater Tank

Terrible Advice Tuesdays (T.A.Tues): Clean Fish Food Doesn’t Have This In It


Terrible Advice Tuesdays:  “Brand XYZ of fish food has zero phosphates in it”

The rest of the story: Fish food is made up matter that was once alive such as algae or fleshy foods like mysis or brine shrimp just to name a few. Inside living matter or matter that was once alive, lies phosphates as phosphate is an integral part of tissues, DNA, proteins, etc. Therefore, saying a fish food is phosphate free is misleading and inaccurate.

I can see how someone could say their food doesn’t have any phosphates added to the food, but that doesn’t make their food phosphate free.

Finally, if someone said the above statement to me, I’d smack them and scold them for starving my fish. Fish need phosphates to live and food is the best source of these phosphates.

Browse the Store! Questions?

Comments for this article (5)

  • Oh what big business wont say or do to make a dollar…

  • bruce d waterat says:

    Mark, What’s your take on running a GFO reactor to control phosphates. I have a 90g mixed tank and I run a mix of GFO & carbon in one reactor, this has reduced my phosphate levels to undetectable via a Hanna checker.

  • bruce…I run GFO on nearly all my tanks

  • Chris Longstreth says:

    Thanks Mark. Any thoughts on rinsing frozen food? I’ve seen forum posts and my lfs insist on it, yet like everything else in this hobby, I’ve also seen people insist it isn’t necessary. I’m chasing a hair algae problem and I feed minimally and run GFO. Rinsing has been recommend but I have my doubts on effectiveness.

  • Corry says:

    Actually you can have phosphate free fish food as it is regulated by the FDA. The FDA considers any single vitamin/mineral(like PO4) that is less than 3% of the total volume to be “Free” or 5% to be “Low” of that substance. While complex things like fats and sugars at 1% to be “Free” and 3% to be “Low”. its the same for human food. Ever wonder why seemingly high fat dairy products can be ‘Low Fat’ or desserts ‘Low Sugar/Sugar Free”. But in our fish food (especially fresh/frozen because of all the water weight) 3% is enough to eventually crash a tank.

Comments are closed.