Terrible Advice Tuesdays (T.A.Tues): This Fish Food Is Phosphate Free…(yeah right)


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.

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Comments for this article (17)

  • Arthur says:

    Thanks for the tip. I don’t know where you come up with all this, but thanks! Lol

  • Tony says:

    Thanks Mark. Good point!

  • Tony says:

    Thanks Mark! Good point!

  • JasPR says:

    Mark, you are the marine hobby’s version of ‘myth busters!” Good for you!

    personally I think that many of these ‘marketing facts’ are misrepresentation in that they never focus on the big picture. And that is, the challenges of keeping living organisms in a CLOSED system. As I’ve said in my own writings and in a book I co-authored– in a closed system, over time, ‘things’ are used up and ‘other things’ are built up. The ONLY escape from this reality is stocking ratio, dilution and more dilution! Returning all parameters to the base line reading is the entire truth of the art and science of our hobby. Best, JasPR

  • Jerry says:

    Why I always advise new, and some older hobbyists to rinse their frozen foods; except Rod’s, with rodi water

    I’ve almost acquired all the materials necessary for my mysid propagation system and; hopefully, between that, my phyto, brine and copepod cultures, I can eliminate a massive portion of “dead” food. One tank is an nps system and the potential labor savings of feeding live; vs the 3lbs of frozen it gets per month now, should be astronomical. If you have any experience, tips or connections in this segment of the hobby, Please share that in an (unlikely to be very short) upcoming episode!

  • Buddy says:

    I really should have paid more attention in those chemistry classes.. Great tip Mark !! Is there a test on this Friday ? 🙂

  • Adam Blanden says:

    FINALLY, someone discussing phosphate as an essential nutrient necessary to all life rather than the bane of all things salty. I would only add that not only fish, but corals require phosphate as well — even our beloved SPS. We often talk about phosphate as a bad thing because it inhibits calcification and allows nuisance algae to grow, but the corals’ tissues and zooxanthelle also require it to live and grow. If we were to truly have 0 phosphate in our water (not just undetectable, but truly 0), our corals would stop growing, bleach, and eventually die, just like the fish 🙂

    Great point!

  • Tim says:

    What is an acceptable mg/L for phosphate. Both for fish only and in a coral/fish tank?

  • Tim says:

    What is an acceptable mg/L for phosphate. For fish only and in a coral/fish tank?

  • J.A. says:

    Many thanks for all the stuff you teach here!
    Hi fron Spain!!

  • Frank says:

    Good stuff Mark! You never disappoint.

  • Jimbo says:

    Some very good points here i especially liked the comment from JasPR well said !

  • Sparkgk711 says:

    Mark your a gangsta at this

  • Mike says:

    What is the best recommended (dry) food that most use?

  • JasPR says:

    foot note, however– fish gain 95% of their needs from diet. And so phosphates in water and phosphates ( bone, shells etc) are two different things.
    In addition, “what goes in” is partly “what comes out” as not everything is ingested, digested and absorbed. The entire subject of DOCs is part of the story of “what comes out partly digested”. So the train of things going into the closed system is one of conversion and change more than ‘something to nothing’. Most of you know that algae and bacteria- Give back,upon death, all they store in life. These cells can recirculate lots of trapped chemicals and molecules back to the environment. But I digress– still food for thought. JasPR

  • Klaas Oreel says:

    Great advice Mark. I grow macro algae in my sump tank to take out phosphates. So far levels have been very low. Greeting from the Philippines

  • Lucas Cronin says:

    Mike, look in to New Life Spectrum, Cyclopeeze, Ocean Nutrition, and Spirulina Flakes.

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