Green water and fish breeding

[redfish]

I have green water in my outdoor tub.  Is this good for guppies to breed or raise fry?  Should I clear up the water before adding fry or adults?  The tubs have mosquito larvae also.

Parameters look fine and mostly match my inside tanks since I used that water to start the tub.

Sample:

 

Any other info or ideas on what to do with green water?  Most info I’ve read has been about removing it.

[Scapexghost]

Good for breeding. Keeps water clean, makes it harder for adults to see the babies, and serves as a food source for the babies.

[lefty o]

ive never had green water, but it is supposed to be fantastic for breeding/fry.

[AnimalNerd98]

Fry will have an endless food source. You can use this to feed daphnia cultures too! Adult fish also love green water, especially for fish that are not from clear water conditions. I remember in the old tour of Lamont’s fish room, he talked about how he put his rescue bettas in his green water tank and they would come out colored up and fattened up. https://m.youtube.com/watch?v=EDCPFTi72io&t=1819s

[redfish]

Would you consider green water “cycled”?  It looks like the fish would have a hard time breathing and swimming but I’ll add some fish.  
 

I’m thinking about grabbing 5 gallons in a smaller tub and bringing it inside so I can monitor the fish easier. 

[Chick-In-Of-TheSea]

I've read plenty of posts about people trying to make green water, and here you just ended up with it.  Congrats! 🙂 

[gardenman]

On 9/23/2022 at 8:05 AM, redfish said:

Would you consider green water “cycled”?  It looks like the fish would have a hard time breathing and swimming but I’ll add some fish.  
 

I’m thinking about grabbing 5 gallons in a smaller tub and bringing it inside so I can monitor the fish easier. 

In general, water doesn't get cycled, but tanks do. Beneficial bacteria need something to attach to (hardscape, gravel, filter media, tank walls, etc.) and not just hang out in the water. There are some bacteria in the water, but the real populations are on the hard stuff. The more hard stuff you have in a tank, the more beneficial bacteria you tend to have.

Breathing in algae filled water is interesting. During daylight hours, algae, like all plants, breathe in CO2 and exhale oxygen, so during the day an algae filled tank/tub is probably easier for a fish to breathe in than a "clean" tank/tub. At night things get reversed. The algae strips oxygen from the water and the fish can be in trouble if there's a lot of algae all taking the oxygen from the water. Massive fish kills, whether in commercial fish farming or home ponds, often take place overnight when the oxygen gets depleted, and the fish suffocate and die. In deep ponds stratification can lead to massive fish loss when the stratified layers get disturbed. In a tank setting, something simple like an airstone or surface agitation from a filter return will prevent too much oxygen depletion overnight, but without that, things can get messy if you've got a lot of green water. 

In general, green water is a good thing if you're trying to keep fish. Not great to look at, but good for the fish. Just avoid extremes.

[MattyM]

I had a preg platy that seemed like she was never going to drop her fry. Then I accidentally triggered an algae bloom that went on for a couple weeks. Now that it's clearing up I have 5 or 6 spunky, healthy fry. 

[lefty o]

On 9/23/2022 at 8:18 AM, gardenman said:

In general, water doesn't get cycled, but tanks do. Beneficial bacteria need something to attach to (hardscape, gravel, filter media, tank walls, etc.) and not just hang out in the water. There are some bacteria in the water, but the real populations are on the hard stuff. The more hard stuff you have in a tank, the more beneficial bacteria you tend to have.

Breathing in algae filled water is interesting. During daylight hours, algae, like all plants, breathe in CO2 and exhale oxygen, so during the day an algae filled tank/tub is probably easier for a fish to breathe in than a "clean" tank/tub. At night things get reversed. The algae strips oxygen from the water and the fish can be in trouble if there's a lot of algae all taking the oxygen from the water. Massive fish kills, whether in commercial fish farming or home ponds, often take place overnight when the oxygen gets depleted, and the fish suffocate and die. In deep ponds stratification can lead to massive fish loss when the stratified layers get disturbed. In a tank setting, something simple like an airstone or surface agitation from a filter return will prevent too much oxygen depletion overnight, but without that, things can get messy if you've got a lot of green water. 

In general, green water is a good thing if you're trying to keep fish. Not great to look at, but good for the fish. Just avoid extremes.

pretty much. i really detest the whole "cycled" thing. you have a sufficient quantity of bacteria to handle the tanks needs, or you dont.

[modified lung]

I'll also stress the importance of good aeration with greenwater. Without it not only will your oxygen crash at night, your pH can rise to lethal levels during the day. Aeration will prevent both of these.

The greenwater will eat ammonia, so in a sense the tank is cycled but with microalgae instead of bacteria. But just like bacteria, there needs to be enough microalgae to eat it all. Populations of microalgae can be a lot more volatile than populations of nitrifying bacteria.

Also keep in mind the greenwater is competing with your bacteria for ammonia and bicarbs/CO2 which means you'll have a lot less bacteria over time. If the greenwater disappears, your bacteria population won't be large enough to handle the ammonia.

Another thing to keep in mind is the fry don't eat the greenwater itself; they eat the microorganism that eat the greenwater. If your fry all grow up or are moved, there won't be anything to keep those microorganisms in check. They'll grow in population extremely fast and consume all the greenwater in a couple days.

[redfish]

I appreciate the responses.  PH reading is much higher (over 8.5) than my inside tanks(~7.0).  I'll need to get that lower to avoid shocking any fish before adding them.

On 9/23/2022 at 7:55 AM, Chick-In-Of-TheSea said:

I've read plenty of posts about people trying to make green water, and here you just ended up with it.  Congrats! 🙂 

I've been preparing the tubs for a month or more now.  Adding some easy green, tank water, driftwood blackwater and some plants trying to get the water ready for fish.  I also let the tubs grow mosquito larvae.  I recently added a sponge filter to each tub.  Now that I have it, I wanted to make sure it was safe to use.

Ideally, I would not mind if the tubs cleared up like my inside tanks but this will be an interesting experiment.  I just don't want to kill any fish in the process.

On 9/23/2022 at 11:51 AM, modified lung said:

I'll also stress the importance of good aeration with greenwater. Without it not only will your oxygen crash at night, your pH can rise to lethal levels during the day. Aeration will prevent both of these.

This may be what is causing the high PH.  I just recently added the sponge filter.  Before everything went green, the PH was pretty neutral.

[modified lung]

On 9/23/2022 at 12:15 PM, redfish said:

This may be what is causing the high PH.  I just recently added the sponge filter.  Before everything went green, the PH was pretty neutral.

It's because the greenwater is consuming CO2 and KH. Adding enough baking soda will stabilize your pH around 8.2 but it might not last long. pH 9 is where the lethal threshold starts for a lot of fish species. Just aeration should keep it below 9 though. If it gets too close for comfort, just water change out some of the greenwater.

[rockfisher]

I have guppies in green water tubs outside in South Florida. I do have aeration in them. I did saw a few loses at the beginning of summer  when temps started hitting 92. As summer is almost over it may not be issue now. Oxygen is lower in warmer water. Other than those loses in have not had any issues. I think the should be good. My concern with change water parameters by add to the pond,tank,tubs is this is mostly a solution that you I might have to do all the time. Honestly I think they will be ok with the change. I would think about adding a few more fish if you are buying them. Just because it’s added stress to the fish. 

[redfish]

On 9/23/2022 at 3:31 PM, modified lung said:

It's because the greenwater is consuming CO2 and KH. Adding enough baking soda will stabilize your pH around 8.2 but it might not last long. pH 9 is where the lethal threshold starts for a lot of fish species. Just aeration should keep it below 9 though. If it gets too close for comfort, just water change out some of the greenwater.

Thanks.  The PH is reading really high.  I’ll test tomorrow again.  Normally I aerate to raise PH but that’s with clean water.  I understand/am learning  green water is a bit different.  I added some driftwood also to see if that helps any.  I’ll do a water change tomorrow if PH still high.

Edited:  I use baking soda to increase PH in clean water also.

Edited September 24, 2022 by redfish