Yet another cycling question

[OscarsAreCool]

Kept fish most of my life (community, discus, mbuna), but stopped ~10 years ago, now back into it since ~1 year ago. Always wanted oscars but no room till I moved to this new house. So I got a brand new 210g - and this is first time trying seeding my filter with bacteria from a mature tank. I have a very established 40g breeder (9 months old, thriving). I took 4 large handfuls of gravel and shoves them into media bags. I have 2x FX6s on the 210, so I put two bags of gravel in each FX6, in the same trays as the new bio media (ceramic rings). I also threw a couple of decorative hiding rocks from the 40g into the 210g, figured it could only help a tiny bit more.

Early research and asking some LFS folks said I'd be good to go on day 1, just don't add too many fish at once - makes sense. Added 3 baby oscars (1x 3", 2x 4"), 1 adult angel (from timeout tank), and 1 juvenile (4") pike cichlid (also in timeout, soon to be re-homed - long story, sold as dwarf pike cichlid, buyer beware). Maybe that was too much, however the pike, the angel, and 1 of the 3 oscars were, and still are, doing just great. Eating, active, not hiding from me, all the good signs. However 2 of the 3 oscars didn't do well and ended up dying. Now - the 2 that died were tiger oscars, about 1" longer than the one that made it. The surviving oscar is a red oscar, not sure that it matters. The 2 tigers were pretty much identical in size, in the same store tank, implying different hatches, maybe different breeders/origin altogether vs the red oscar.

I had been testing ammonia/nitrite/nitrate every day since setup, reading 0's every day, then after ~6 days of feeding I did have a ~0.25ppm ammonia reading. I did a 50% water change, and that's when the 2 oscars started going downhill. Remember, the other 3 fish were fine the whole time. The very next day I was reading 0 ammonia, 0 nitrite, and starting to see non-zero amounts of nitrate. I also took a sample of water to my LFS that same day, and they actually read ~0.5ppm ammonia. This started making me crazy, so every day for the last week I've been testing 2-3x per day. API test kits, nothing expires till 2026/27. I'm making sure to shake the bottles very well before use, uniform droplet size, not use my finger tip to seal the test tube, read test exactly 5 mins later, etc - trying to do all the things just right. I even bought a 2nd ammonia kit, always the same readings. I keep reading 0 ammonia, 0 nitrite, and now I am most definitely seeing nitrates go up and up (haven't done a water change since that 1st one mentioned before, so 1 full week since water change). Nitrate ~5-10ppm right now. I also have early algae starting 3-4 days ago. I am seeing more and more 'dust' algae spreading over the glass & rocks, noticeable amounts, more each day, but not unexpected amounts or anything.

Right now, the fish in the tank are super active and eating well. My gut says the tank is cycled, and I can slowly add more fish, but losing those 2 oscars has me a little upset, I got attached to those oscars pretty quick...

Now, my questions - and happy to provide any pics or whatever additional info can help.

• Was the 50% water change on day 6 a mistake? I was trying to follow what I've learned re. ammonia spikes, but some have said maybe that was a mistake and I should have let it settle on its own.
• Do you folks think it is more likely that the 2 fish that died were from a weaker genetic line? I.e. the 2 that died were from the same clutch, the 1 that survived was from a different clutch. Or, do you think its more likely that the angel, pike, and surviving oscar were of extremely hardy genetic lines? My gut screams the former - whereas had the angel or pike also died, I would say the surviving oscar was just from an exceptionally hardy line.
• I heard that until I see a nitrite spike, I'm not cycled. My gut says that is false, if my seeded filters are indeed transitioning well. I.e. the .25ppm ammonia was understandable if I overfed too soon. But, if I never see nitrites, but I do see nitrates getting higher and higher, I want to assume I will never see that nitrite spike.
• Can anyone think of any reason the LFS measured such a high ammonia difference than myself at home? I did put the water in a tupperware container - maybe that had some residue on it? It was ~15 mins to the store, could there have been some debris I didn't notice that broke down that fast on the drive over? I dunno - going back tomorrow for another test, this time I plan to put water in a brand new plastic ziplock bag.

 

[OscarsAreCool]

Additional notes as I sit here thinking about it:

• Re. the 2x tigers' questionable hardiness - I remember seeing at least 1 other dead tiger oscar of that size/in that same tank at the LFS too they day I had them test my water - so that particular 'demographic' of oscars are dying at the LFS too, not just my tank. LFS is fairly reputable in the area and I have bought many fish from them with no issues.
• I also have 1 medium (5") rhino pleco that I added on day 4, surely contributed to bio load a bit. Added 1 wafer that he didn't eat, removed it after 2 days, planning to try again this weekend. That uneaten wafer surely did add to the ammonia spike on day 6. Probably should have removed it next day.
• Temperature is 79F
• I've since moved the pike cichlid back to the timeout tank - so today there is only the angel, the red oscar, and the pleco in the tank.
• I've been feeding very lightly 3-4x per day for the last 5 days, since basically it's just the red oscar & angel. Xtreme sinking & floating pellets, bloodworms, brine w/ spirulina, dried krill - tried vibra bites but oscar wouldn't take it
• The pleco has algae on the rocks I transferred from the 40g, and I have wafers & cucumbers that I plan to start trying this weekend. That algae grows back more and more each day on these rocks, right now I'd say they have ~10-15% of the algae volume as when I added them.
• Water is very clear today. Few days ago seemed a wee bit cloudier. Not sure if that was a slight bloom or not. No foul smells.
• Washed play sand substrate

 

[Azedenkae]

• Was the 50% water change on day 6 a mistake? I was trying to follow what I've learned re. ammonia spikes, but some have said maybe that was a mistake and I should have let it settle on its own.

Because this is a fish-in cycle, it is never a mistake to do a water change. Just to solve the question at its roots, what information did you find that would say water changes was a mistake when fish-in cycling?

• Do you folks think it is more likely that the 2 fish that died were from a weaker genetic line? I.e. the 2 that died were from the same clutch, the 1 that survived was from a different clutch. Or, do you think its more likely that the angel, pike, and surviving oscar were of extremely hardy genetic lines? My gut screams the former - whereas had the angel or pike also died, I would say the surviving oscar was just from an exceptionally hardy line.

Unfortunately this is not a question answerable right now. Generally people test parameters from the get go, and that is how one figures out if it may be due to water parameters. For example, if the parameters are all within the safe zone and the fish died anyways, then it'd be an issue with the fish. No way to know in hindsight hough.

• I heard that until I see a nitrite spike, I'm not cycled. My gut says that is false, if my seeded filters are indeed transitioning well. I.e. the .25ppm ammonia was understandable if I overfed too soon. But, if I never see nitrites, but I do see nitrates getting higher and higher, I want to assume I will never see that nitrite spike.

You are correct. There is a graph that is spread around the internet often, the one that shows ammonia spike, then nitrite, then nitrate. 95% of the time nowadays it is not applicable, for a whole host of reasons. Using seeded filters does mean you can have quite a bit of nitrifiers already, and in such cases it is absolutely common to not see nitrite spike (as any ammonia converted to nitrite is instantly converted to nitrate). By the way, 0.25ppm ammonia is a very common false positive measurements on API test kits. Not saying it is absolutely the case for you, just something to keep in mind.

• Can anyone think of any reason the LFS measured such a high ammonia difference than myself at home? I did put the water in a tupperware container - maybe that had some residue on it? It was ~15 mins to the store, could there have been some debris I didn't notice that broke down that fast on the drive over? I dunno - going back tomorrow for another test, this time I plan to put water in a brand new plastic ziplock bag.

When you do your own testing, do you shake the vial vigorously between adding drops from bottle #1 and #2? Do you shake vigorously after? Also, make sure to read the test at the 5 min. Earlier or later may not be accurate.

 

[duanes]

When you add viable seasoned media to a new tank. there is a possibility you will never see a positive test for nitrite.
You are not really going to go thru the traditional cycle that way, you are skipping all phases by using the seasoned media.
In a tank I set up 3 years ago from scratch (a 180) I never saw the 3 stage cycle, because about month before I added fish, I added lots of plants collected in a local lake. (a similar situation to adding seasoned media)the plants are also covered in beneficial biofilm.
In fact in almost 4 years, since it's been set up, I have never had any results testing for ammonia, nitrite or even minimal nitrate.
As soon as I added fish (month later) I started doing water changes though, I try to do a 30-40% water change every other day.
My first group of sacrificial fish were about 2 dozen mosquito fish, but none were sacrificed in the transition, until they only were eaten by cichlids, when I was convinced parameters posed no threat.

Let me stress when I say I added plants, I did not mean just a few, I do not want to have someone think a few Vals and a sword would be sufficient to poo poo a cycle.
By the time I added substantial fish the planting was, (as in the pic below), at a point where some of the Val were almost 2 feet tall.

I have a feeling the 2 oscars were already sick, when seeing the dead ones in the tank that day, would have given pause, and I would have passed on any from that tank.
Most LFSs pull dead fish before opening the doors, so seeing 2 more dead later, would tell me that oscar group was already compromised with a disease, or something.
Today, my major filtration mode is by a 125 gal planted refugium.

 

[OscarsAreCool]

Thanks!

Because this is a fish-in cycle, it is never a mistake to do a water change. Just to solve the question at its roots, what information did you find that would say water changes was a mistake when fish-in cycling?

• Someone said 'maybe' the water change created even more ammonia than what little was already in there. I intended this to be an auto-cycle with the established media, not even a fish-in cycle at all, which is why I'm sort of bothered by the dead fish.

Unfortunately this is not a question answerable right now. Generally people test parameters from the get go, and that is how one figures out if it may be due to water parameters. For example, if the parameters are all within the safe zone and the fish died anyways, then it'd be an issue with the fish. No way to know in hindsight hough.

• 10-4

You are correct. There is a graph that is spread around the internet often, the one that shows ammonia spike, then nitrite, then nitrate. 95% of the time nowadays it is not applicable, for a whole host of reasons. Using seeded filters does mean you can have quite a bit of nitrifiers already, and in such cases it is absolutely common to not see nitrite spike (as any ammonia converted to nitrite is instantly converted to nitrate). By the way, 0.25ppm ammonia is a very common false positive measurements on API test kits. Not saying it is absolutely the case for you, just something to keep in mind.

• Explains a lot & good to know

When you do your own testing, do you shake the vial vigorously between adding drops from bottle #1 and #2? Do you shake vigorously after? Also, make sure to read the test at the 5 min. Earlier or later may not be accurate.

• Definitely - took extra care with all instructions.

Pretty confident my readings are good and I'm to slowly add fish.

 

[OscarsAreCool]

When you add viable seasoned media to a new tank. there is a possibility you will never see a positive test for nitrite.
You are not really going to go thru the traditional cycle that way, you are skipping all phases by using the seasoned media.

• This was my intention - just the dead fish and some folks at the LFS made me second guess everything (which is fine, glad good folks on this forum are here to help)

I have a feeling the 2 oscars were already sick, when seeing the dead ones in the tank that day, would have given pause, and I would have passed on any from that tank.
Most LFSs pull dead fish before opening the doors, so seeing 2 more dead later, would tell me that oscar group was already compromised with a disease, or something.

• I saw the dead fish at the LFS after mine had died, but yeah my gut also says that group had something wrong from the start. Lesson learned.

Thanks!!