Are my pygmy corys getting enough food?

Gemtrox42

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For context, I have a 30 gal tank with Current Satellite LEDs, moderately planted with gravel bottom, mostly hornwart, water sprite, swords and java ferns, lots of driftwood. My fish are 15 cardinals, 8 pygmy corys and 5 cherry shrimp. I have two female lyretail mollies and one black sailfin male molly. Water is 78 degrees, hang on back filter so should be well oxygenated. Water parameters are 7.3 pH, ammonia 0, nitrites 0, nitrates 5, GH 50~75, KH 140. I am using softened wellwater. I treat the water with aquavitro seed and dechlorinator/balancer.

I feed my cardinals and mollies about two pinches of hikari floating tetra pellets (which they consume in roughly 40 to 50 seconds) twice daily. I feed my corys 2 hikari sinking wafers, which usually takes 30+ minutes to eat, given the cardinals don't find it. I feed my shrimp about 10 hikari shrimp pellets once daily, and have the same issue with cardinals taking their food. My corys are happily munching on my driftwood fungus though. Although I haven't lost any corys yet, I am worried that long-term they may not be eating enough. If that is the case, what can I do to make sure they get enough to eat?
 

itiwhetu

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Do you feed your cardinals at the same time as the others. I would feed the cardinals at one end of the tank and everybody else at the other. But do it at the same time. The fish soon learn where their food is.
 
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Gemtrox42

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Ok, I have been doing this for a while now and usually 3 or 4 corys find it before they are descended upon by some cardinals and my mollies. Like I said, if they are getting enough food by sharing the wafers and eating fungus and the very few leftovers, I wouldn't worry, but if not I am looking for something else to help them out.
 

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Get them some bug bites pellets, cories are carnivores and shouldn't rely strictly on wafers and biofilm.

Feed them at night when lights are out.

Id also look to rehome the mollies your water is far too soft for them to stay healthy longterm :(
 

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It looks like you already got some good answers to your question, but I wanted to touch upon something else you said. You said you use softened well water to fill your tank with. Does this mean that you have a water softener system at your house? Is it the kind that you put salt or potassium chloride crystals into? If so, you will need to use water that does not go through the system to fill the tank, since using the "softened" water will contain too many sodium ions which will be harmful to your fish. If your water is very hard, you may need to look into keeping fish that are only suited to hard water, or you may need to consider mixing in RO water to soften your water (mixing in water with no dissolved ions to bring down total number of dissolved ions).

look up @Naterjm he recently posted a few threads on this topic since he was struggling with the same issue at his house.
 

mcordelia

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also totally didn't mean to contradict @NCaquatics about the molly thing - she was looking at the GH/KH numbers, I was looking at the term "softened well water". Let's get to the bottom of this so we can help you best!!
 
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Gemtrox42

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Get them some bug bites pellets, cories are carnivores and shouldn't rely strictly on wafers and biofilm.
Ok thanks. Do I need to worry about my other fish eating those too?
Feed them at night when lights are out.
Fantastic suggestion, thanks. Will start trying that immediately.
Id also look to rehome the mollies your water is far too soft for them to stay healthy longterm :(
I have read this from many people on the forums, personally I have been keeping mollies for about 3 years using the same water, and neither of the fish hobbyists I go to have cautioned me against getting mollies with my parameters. Can you elaborate a bit on what you mean by long term? Not saying you are wrong, just curious because of the contrary info I've gotten.
 

mcordelia

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Here is a thread that discusses water hardness with relation to freshwater fish: https://www.fishforums.net/threads/effect-of-hard-water-on-soft-water-fish.464894/#post-3975997

Mollies, specifically, from what I understand are susceptible to an illness called the "shimmies" when they are kept in water that is too soft.

But I am still curious, is your water soft or hard? I understand that those are your test results, are they from the API test kit, or your well report? Also, do you have a water softener system that needs to be recharged monthly for example?
 
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Gemtrox42

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It looks like you already got some good answers to your question, but I wanted to touch upon something else you said. You said you use softened well water to fill your tank with. Does this mean that you have a water softener system at your house? Is it the kind that you put salt or potassium chloride crystals into? If so, you will need to use water that does not go through the system to fill the tank, since using the "softened" water will contain too many sodium ions which will be harmful to your fish. If your water is very hard, you may need to look into keeping fish that are only suited to hard water, or you may need to consider mixing in RO water to soften your water (mixing in water with no dissolved ions to bring down total number of dissolved ions).
Thank you for the advice. I do use sodium chloride to soften my well water. However like I said to NCaquatics, I've done it for years and haven't been told its dangerous to my fish. Again, not saying I disagree, but I have never heard of this from research or my stores.
 
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Gemtrox42

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Here is a thread that discusses water hardness with relation to freshwater fish: https://www.fishforums.net/threads/effect-of-hard-water-on-soft-water-fish.464894/#post-3975997
Thanks, reading now.
Mollies, specifically, from what I understand are susceptible to an illness called the "shimmies" when they are kept in water that is too soft.
Yes I have heard of this. My mollies are fairly active however. I appreciate the support, I will make a post in live bearers addressing this. Trying to stay on topic.
But I am still curious, is your water soft or hard? I understand that those are your test results, are they from the API test kit, or your well report? Also, do you have a water softener system that needs to be recharged monthly for example?
My wellwater is hard. Not sure by how much, I can check if it's important I guess. The test results are from a Freshwater Master kit, used on my aquarium water. The softener is recharged monthly with new salt pellets. In case it matters, I have it set to demand mode instead of delayed for regeneration, the latter of which is more common I understand.
 

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Softeners can be detrimental to fish, the sodium content isn't good for freshwater fish either. Especially corydoras
 

mcordelia

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Also, you can take a look at this:

Basically the way it works is this: fish, like most animals, regulate what is inside their body relative to the environment outside their body. In people, when you feel dehydrated (your body actually knows you're dehydrated because you have too many ions in your blood and you have cells in your body that can detect this [OVERSIMPLIFICATION]), you drink some water, and when that water goes from your gut to your blood, the ion concentration decreases and you no longer feel thirsty. As you know, when you sweat you release both water and salt, and that's why they tell you to drink gatorade during hot weather while exercising since it helps replenish both the salt and the water inside your blood so that your body is happy. It is possible for a human to die from drinking too much water as well, this is called hyponatremia, there was a famous case in the USA where a radio station had a competition of who could drink the most water and someone died (you can google that).

Humans aren't fish, so the way it works in fish (from what I understand) is this: Fish, because they live in water, have systems that allow ions to pass through their gills and their intestine. The cells in these systems are either very "porous" to ions or don't let a lot of ions go through, and that is dependent on the genetic code of the fish based on what type of water they have been raised in. Most livebearers for the aquarium trade are raised in hard water, so their internal systems are best suited to dealing with hard water, and as a result, their cells are quite porous to ions since it doesn't matter if they lose a bunch of ions to the environment, since they can just as easily replenish them. Softwater fish such as neon tetras on the other hand, have very 'locked up" cells that hold tightly to ions, since where they are originally from ions in water are harder to come by, and it is important for the fish to maintain the ions that they are able to acquire through their diet etc. Some fish, especially those that come from areas that see periodic rainy and dry seasons, have systems that they can calibrate to either be porous or locked, and depending on the season (dry season: harder water, rainy season: softer water) they can adjust how many ions their bodies hold onto.

The first organ that usually goes when the hardness is not optimal is the kidney. In humans (again, I know fish are not humans), the kidneys have a huge reserve (why you can donate one kidney to someone and still be fine), and kidney diseases tend to be relatively asymptomatic until the very late stages (people complain of itching and puffiness). If fish are anything like this (I don't have any knowledge of fish physiology), then their kidney issues could also get very advanced before they start showing external symptoms.

However, with a declining kidney status, the overall immune system cannot fight diseases off as well as it would otherwise, and fish can otherwise be susceptible to other irritants or issues in the water that would not normally kill a fish. So the fish don't necessarily die of "hardness issues", but they are in overall worse health and will more easily die from a bacterial/fungal/viral infection, or may not bounce back from a pH shift or other water quality issue like other fish might. Thus, the fish might die an "explainable" death, which cannot be necessarily directly attributed to hardness issues, but the hardness issues helped that other problem arise.

I hope this explanation was helpful/made sense. Again I am not a fish physiologist or anything, but this is how I have understood the situation.
 

mcordelia

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one more thing on the water softener: The way a rechargeable whole-house softener system works is there is a resin that is periodically recharged by sodium chloride or potassium chloride. This works in a way that larger ions like magnesium and calcium are exchanged for sodium, so that the Mg and Ca get trapped in the water softener system and flushed out during the cleaning, and the Na is released into the water that goes through the house. For many appliances, etc, it is better to have Na ions as the prevalent ion instead of some of the other ions, and from what I understand it also feels more pleasant on your skin to have high-Na water instead of water that is predominantly high in other minerals. Many soaps and detergents are also formulated to more easily dissolve into "softened" water.

However, from a fish's perspective, all the softener is doing is changing the proportions of the ions, not the total number. the water will still be "hard", it just won't have high Mg and Ca concentrations. That is probably why your GH/KH test kit is reading so low, because I don't think the test measures sodium ions. What you're effectively doing with a water softener system is mixing salt into your water, which isn't good for freshwater fish. In humans, excess Na causes hypertension and heart disease, both by affecting the function of the kidneys as well as your blood vessels. I'm not sure if it's the same in fish, but it seems to be that "all roads lead to Rome" where the kidney is really the central organ that is affected by mineral/ion imbalances.

If you wish to keep softwater fish, you will need to mix in RO water to water directly from your well (not from the softener) to bring down the hardness. If you wish to keep hardwater fish, your well water should be ok to use as-is, just make sure to use the bypass valve of the softener (or any tap that doesn't receive softened water) as the source of water for your fishtank :)
 
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