Who Gives A Fish Forums

They're not needed.
All living creatures, from the tiniest mice to massive elephants, and from humans to our canine friends, require macronutrients and trace elements to survive. Where do these essential nutrients come from? It's simple: food. Fish food, just like our own food, contains the necessary macronutrients and trace elements for healthy living - in other words, fish food serves as fertilization.
A well-planned feeding routine, regular water changes, and a suitable filtration system are more than enough to keep both fish and plants thriving.

While fish food does contain the necessary nutrients for plant growth, there's often an imbalance - too much nitrogen and not enough iron, calcium, or magnesium. To grow healthy plants using just fish food, you'd likely need a substantial number of fish, which could lead to issues maintaining optimal ammonia, nitrite, and nitrate levels. This approach is particularly challenging for smaller tanks.

It's worth noting that fish can obtain some nutrients from the water itself. However, in areas with very soft water or tanks using RO water, it can be extremely difficult to achieve plant growth, even with reputable fertilizers. I learned this the hard way when setting up my small aquarium. Initially, I thought fish waste would be sufficient, but with my tap water testing poorly, I switched to RO water. Unfortunately, my plants struggled to survive. Only after switching to fertilizers did I see some improvement, but growth was still subpar.

It wasn't until I created a custom fertilizer, assuming my water had zero nutrients, that I finally achieved decent growth. This experience taught me that commercial fertilizers often rely on the water providing some of the necessary nutrients, which wasn't the case in my situation.

It's not one recipe, but I'll give you an idea of what I did. Plants need macronutrients and micronutrients.

The macronutrients are Nitrogen (N), Potassium (K), Calcium (Ca), Magnesium (Mg), Phosphorous (P), Sulfur (S), and Chlorine (Cl). You can buy premixed bottles for NPK nutrients, like potassium nitrate and potassium phosphate. I used Seachem's individual bottles for N, P, and K, and a GH booster for Ca and Mg. I aim for 1 ppm nitrate and 1 ppm phosphate.

For micronutrients, you need Iron (Fe), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), Molybdenum (Mo), and Nickel (Ni). My first micro recipe used:
- Fe DTPA at 0.1 ppm
- MnSO4 at 0.05 ppm
- H3BO3 at 0.02 ppm
- ZnSO4 at 0.02 ppm
- CuSO4 at 0.01 ppm
- Na2MoO4 at 0.005 ppm
- NiSO4 at 0.005 ppm

Note that 1 ppm is one milligram per liter. I used Rotalabutterfly.com's aquarium fertilizer calculator and a cheap milligram scale to calculate the weights. I entered the tank size, selected DIY, and chose the compound. Then I selected liquid solution and entered the volume of water.

After calculating, I measured out each nutrient and filled a bottle with distilled water and 2 ml of distilled vinegar. The vinegar helps everything dissolve and prevents iron oxidation. I added all the nutrients and mixed. It takes an hour or two for everything to dissolve. The resulting fertilizer should be amber-colored.

For my 5-gallon shrimp tank, one 1-ml dose once a week was enough. I also did a 50% water change once a week. After the water change, I dosed the needed amount of GH booster, added my macronutrients, and then added the micronutrients. This worked well for over a year before I had a problem.

I eventually found that Sodium Molybdate reacted with my other micros, making Molybdenum unavailable to the plants. I solved this by mixing Sodium Molybdate with my nitrate and phosphate bottle and removing Molybdenum from the micro recipe. I'd like to mix everything in one bottle, but the calcium in the GH booster doesn't dissolve when mixed with potassium or phosphate. I also don't want to mix nitrate with micros because that would cause mold problems.

You can find many ingredients on Amazon.com, but I purchased Fe DTPA and Sodium Molybdate in one-pound quantities. For the others, I bought them from Loudwolf.com in 4-ounce bottles.

This recipe works well for plants, but my shrimp didn't reproduce. I've been experimenting with adding lithium, iodine, sodium, bromine, vanadium, cobalt, and selenium to the plant fertilizers. My shrimp population went from 5 to 30. Plants don't need these, but animals do.

If you're using tap water, you might want to adjust the dose to avoid adding too many nutrients. You might need to do an ICPOES lab test to figure out how much of the above nutrients are in your tap water.

shakinStevens wrote: ↑Sun Jun 11, 2023 3:23 pm While fish food does contain the necessary nutrients for plant growth, there's often an imbalance - too much nitrogen and not enough iron, calcium, or magnesium. To grow healthy plants using just fish food, you'd likely need a substantial number of fish, which could lead to issues maintaining optimal ammonia, nitrite, and nitrate levels. This approach is particularly challenging for smaller tanks.

It's worth noting that fish can obtain some nutrients from the water itself. However, in areas with very soft water or tanks using RO water, it can be extremely difficult to achieve plant growth, even with reputable fertilizers. I learned this the hard way when setting up my small aquarium. Initially, I thought fish waste would be sufficient, but with my tap water testing poorly, I switched to RO water. Unfortunately, my plants struggled to survive. Only after switching to fertilizers did I see some improvement, but growth was still subpar.

It wasn't until I created a custom fertilizer, assuming my water had zero nutrients, that I finally achieved decent growth. This experience taught me that commercial fertilizers often rely on the water providing some of the necessary nutrients, which wasn't the case in my situation.

Thank you for sharing your recipe, it's incredibly helpful. I'll have to look into the availability of those compounds in my area, but it's definitely given me some new options to consider. My tap water is a bit of a mixed bag, with varying nitrate levels and likely high phosphate levels due to the added phosphorous at the source. I've often thought about switching to RO water, not just for the potential benefits to my plants, but also for the increased flexibility when it comes to choosing fish. Your recipe has made me reconsider this option, as it would allow me to have more control over the nutrients in my tanks.

I really appreciate the time and effort you put into writing this out - it's clear that it wasn't a quick task. I'll definitely be bookmarking this for future reference, as plants are a crucial part of all my tanks, often taking center stage over the fish themselves.

shakinStevens wrote: ↑Sun Jun 11, 2023 3:23 pm While fish food does contain the necessary nutrients for plant growth, there's often an imbalance - too much nitrogen and not enough iron, calcium, or magnesium. To grow healthy plants using just fish food, you'd likely need a substantial number of fish, which could lead to issues maintaining optimal ammonia, nitrite, and nitrate levels. This approach is particularly challenging for smaller tanks.

It's worth noting that fish can obtain some nutrients from the water itself. However, in areas with very soft water or tanks using RO water, it can be extremely difficult to achieve plant growth, even with reputable fertilizers. I learned this the hard way when setting up my small aquarium. Initially, I thought fish waste would be sufficient, but with my tap water testing poorly, I switched to RO water. Unfortunately, my plants struggled to survive. Only after switching to fertilizers did I see some improvement, but growth was still subpar.

It wasn't until I created a custom fertilizer, assuming my water had zero nutrients, that I finally achieved decent growth. This experience taught me that commercial fertilizers often rely on the water providing some of the necessary nutrients, which wasn't the case in my situation.

I've got a low-tech setup going on, lots of small fish swimming about. The two external filters are doing their job, keeping the water parameters in check. My fast-growing sessiliflora and siamensis are looking healthy, but the hygrophila's not doing so great - I think it's lacking in magnesium and possibly calcium too. It's a fast grower, so it needs a bit more love. The plants are doing alright for now, but I might need to make some changes to get some algae growth going, which is a bit ironic, considering I might have to start adding ferts - the very thing I've been trying to avoid.

shakinStevens wrote: ↑Sun Jun 11, 2023 3:23 pm While fish food does contain the necessary nutrients for plant growth, there's often an imbalance - too much nitrogen and not enough iron, calcium, or magnesium. To grow healthy plants using just fish food, you'd likely need a substantial number of fish, which could lead to issues maintaining optimal ammonia, nitrite, and nitrate levels. This approach is particularly challenging for smaller tanks.

It's worth noting that fish can obtain some nutrients from the water itself. However, in areas with very soft water or tanks using RO water, it can be extremely difficult to achieve plant growth, even with reputable fertilizers. I learned this the hard way when setting up my small aquarium. Initially, I thought fish waste would be sufficient, but with my tap water testing poorly, I switched to RO water. Unfortunately, my plants struggled to survive. Only after switching to fertilizers did I see some improvement, but growth was still subpar.

It wasn't until I created a custom fertilizer, assuming my water had zero nutrients, that I finally achieved decent growth. This experience taught me that commercial fertilizers often rely on the water providing some of the necessary nutrients, which wasn't the case in my situation.

In my experience with planted aquariums, elevated fertilizer levels don't necessarily lead to more algae. It's almost as if when plants are thriving, algae struggles to keep up. In my tank, I only have a small amount of hair algae, but no other types like cyanobacteria or black beard algae. My plants seem to grow just a bit faster than the hair algae, so I just manually remove it occasionally to keep it under control. I'm still trying to figure out how to slow it down further, but so far, no luck.

shakinStevens wrote: ↑Sun Jun 11, 2023 3:23 pm While fish food does contain the necessary nutrients for plant growth, there's often an imbalance - too much nitrogen and not enough iron, calcium, or magnesium. To grow healthy plants using just fish food, you'd likely need a substantial number of fish, which could lead to issues maintaining optimal ammonia, nitrite, and nitrate levels. This approach is particularly challenging for smaller tanks.

It's worth noting that fish can obtain some nutrients from the water itself. However, in areas with very soft water or tanks using RO water, it can be extremely difficult to achieve plant growth, even with reputable fertilizers. I learned this the hard way when setting up my small aquarium. Initially, I thought fish waste would be sufficient, but with my tap water testing poorly, I switched to RO water. Unfortunately, my plants struggled to survive. Only after switching to fertilizers did I see some improvement, but growth was still subpar.

It wasn't until I created a custom fertilizer, assuming my water had zero nutrients, that I finally achieved decent growth. This experience taught me that commercial fertilizers often rely on the water providing some of the necessary nutrients, which wasn't the case in my situation.

When I added more sessiliflora, the algae vanished, clearly that plant is hogging most of the nutrients. I can add TNC complete to help with algae growth, but my plecos don't seem too interested in munching on green spot algae.