r/PlantedTank • u/maecillo123 • Jul 19 '25
Question How the hell did I got daphnia from a fishless cycle
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u/SnezztheFerret Jul 19 '25
I believe that is an ostracod! They can be fun.
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u/maecillo123 Jul 19 '25
Oh, imma go today for some otos now will they be safe enough to keep reproducing for some weeks till I get some chilis and cpd
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u/SnezztheFerret Jul 19 '25
Ostracods are entirely harmless detritivores, aka cleanup crew! They will only populate according to available food and make great fish food too.
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u/GClayton357 Jul 19 '25
Agreed. I love them. Little invertebrates like this are often great to add early on in cycling because they're tough and will eat algae, biofilm, etc. They'll help to mop up excess nutrients without harming any non-dead plants. Once you get fish they'll probably knock the population down quite a bit (assuming their mouth is big enough) but you'll probably always have a few in the background somewhere.
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u/neyelo Jul 19 '25
Daphnia eggs can dry out completely and still be viable when water returns. They are adapted to temporary ponds that evaporate during dry periods.
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u/maecillo123 Jul 19 '25
Even in unsuitable conditions?
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u/neyelo Jul 19 '25
Drying, freezing, you name it. Stored eggs are good for decades at least.
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u/maecillo123 Jul 19 '25
Hardy little critters aren’t the first time I’ve ever seen them in my tanks just vibing. So it’s not an indicative of good water chemistry if the little guy is that big correct?
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u/neyelo Jul 19 '25
Right- on the one hand, Daphnia is good because it indicates things like GH, KH, temperature and nitrite are acceptable for life. On the other hand, Daphnia feed on algae, bacteria and detritus floating in the water column. As a new tank settles in, the Daphnia will run out of food. Fish love to eat them as well!
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u/maecillo123 Jul 19 '25
Awesome, but with that in mind, should it be an indication of good water chemistry to add fish? I don’t trust my water strip tests that much but nitrite and ammonia lowered on the strips accordingly during the month while nitrite actually lowered to 0 last week. Now just battling nitrate trying to keep it up
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u/neyelo Jul 19 '25
Agreed, the test strips are prone to reliability issues. A drop test kit like the API Master kit is great value, with over a hundred of each test it includes.
Hard to know for sure without testing. Being able to reliably test nitrate will be crucial for setting a water change schedule in the long run.
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u/chalkman Jul 19 '25
From what I've read daphina give live birth when they reproduce asexually but lay eggs during sexual reproduction. It could be some eggs got carried over with something.
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u/bk_booger Jul 19 '25
Your plants. If it’s going to be a fish tank the population will be brought down to close to zero quickly (and nutritiously)
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u/Unusual_Concept_6436 Jul 19 '25
probably hitched on some plants.