Stocking 40 breeder with corydoras and upside down catfish

[sharkbaithoohah]

I recently adopted from a local community group 6 random corydoras (2 adult sterbai, 2 juvenile bronze, 2 juvenile false juli's) and one 3.5" upside down catfish (Synodontis nigriventris). I thought the sterbai and juli were both juli but realized they are not. Otherwise I would have not got the sterbai because I know they prefer warmer water. They are temporarily in my husband's established planted with sand 20 gallon long.

I am upgrading them to a 40 breeder with black sand, driftwood, anubias, swords and a few stem plants once cycled.
Filter: Seachem Tidal 75 HOB
Heat: 74-75
Water change plan: 25% weekly (unless more needed)

What would be the ideal stocking? I know they all are schooling fish and need groups of 6+ to be happiest. I noticed that the sterbai and juli school together. I don't like keeping sterbai at cooler temperature than they require so was contemplating just increasing the upside down catfish, juli and bronze schools? There is the possibility within the year my sister would take the sterbai and do a proper tank just for them.

Just want to do best by them!

Thank you!

 

[ProudPapa]

It sounds to me like you have a pretty good plan figured out. I'd stick with it.

 

[sharkbaithoohah]

It sounds to me like you have a pretty good plan figured out. I'd stick with it.

What size groups would you recommend for each?

 

[Chiz]

I have some anecdotal evidence, as I have a 29g that is home to 8 (now 10) sterbai that I purchased from a home breeder in 2021. He said he kept them at 72 degrees and even dropped them an additional 1 or 2 degrees to spawn. I have kept them unheated and my house (and tanks) range from 70 to 80 depending on the time of year. Many others say they need it much warmer, so today I did some actual research.

Sterbai are apparently native to the upper Rio Guapore, which indeed, can be as chilly as 68. There is a specific cory named for the region (Corydoras guapore) and most info I see about those suggests keeping those fish at 71-81, which seems to be similar.

I've found a fair amount of data suggesting 73-83 for sterbai, so I think your 75-76 target would be just fine. Some cory are definitely too warm at 80, and sterbai can be OK at 80 or a bit higher so they are used as bottom dwellers in tanks that need to be really warm for other inhabitants. Maybe that is where this train of thought got started.

 

[sharkbaithoohah]

I have some anecdotal evidence, as I have a 29g that is home to 8 (now 10) sterbai that I purchased from a home breeder in 2021. He said he kept them at 72 degrees and even dropped them an additional 1 or 2 degrees to spawn. I have kept them unheated and my house (and tanks) range from 70 to 80 depending on the time of year. Many others say they need it much warmer, so today I did some actual research.

Sterbai are apparently native to the upper Rio Guapore, which indeed, can be as chilly as 68. There is a specific cory named for the region (Corydoras guapore) and most info I see about those suggests keeping those fish at 71-81, which seems to be similar.

I've found a fair amount of data suggesting 73-83 for sterbai, so I think your 75-76 target would be just fine. Some cory are definitely too warm at 80, and sterbai can be OK at 80 or a bit higher so they are used as bottom dwellers in tanks that need to be really warm for other inhabitants. Maybe that is where this train of thought got started.

I heard another person keep them cooler temperatures and they were okay. My concern is they are thriving versus just surviving. It seems like from your anectodal experience/research they do thrive in the low-mid 70's also. I saw on other groups using them with discus frequently, so could see where the idea started.

In that case I could ethically add more sterbai. They are most skiddish so would benefit from increase group of friends. Do you think 25 fish be overkill in the tank? I usually try to understock but the varying species make them a bit more challenging.

 

[Chiz]

More anecdotal info, my sterbai are SO skittish! I even moved them to a tank in a quiet part of the house, but after nearly 3 years, they still seem constantly afraid. I know most cory like some open areas, but these hide a lot, so I've let the plants grow and have added caves and hiding spots. I have never had Juli's (false or otherwise) but I do find the bronze to be outgoing and friendly. I'd probably increase the count of the false juli and bronze to 6-8 each, and keep the two sterbai until possibly your sister takes them. Sterbai are beautiful-- if you get to see them! (p.s. the substrate looks pretty rocky here but they do have a sandy beach)

 

[ProudPapa]

What size groups would you recommend for each?

I'm not familiar with upside down catfish, so I can't help with them, but I don't see an issue with 12-15 of the corys if those two species will be the only stocking.

 

[tinylostwine]

I had an upside down catfish for a year and he was great; got into a really nasty fight with a bn pleco when the pleco tried to steel food he was eating; so there is that aspect. The one i had was solo but my understanding is they do better in a group. He was really outgoing and friendly fellow as long as you didn't try to take the food out from under him. I had mine in a 40b and i presume a group of 4 or 5 would do well but i'd add some slanted driftwood so they have places they can hang out - mango wood or soemthing that have lots of branches. Also you should cover the heater - mine would spend a lot of time resting on the heater and there is the potential for them to get burned.

 

[sharkbaithoohah]

More anecdotal info, my sterbai are SO skittish! I even moved them to a tank in a quiet part of the house, but after nearly 3 years, they still seem constantly afraid. I know most cory like some open areas, but these hide a lot, so I've let the plants grow and have added caves and hiding spots. I have never had Juli's (false or otherwise) but I do find the bronze to be outgoing and friendly. I'd probably increase the count of the false juli and bronze to 6-8 each, and keep the two sterbai until possibly your sister takes them. Sterbai are beautiful-- if you get to see them! (p.s. the substrate looks pretty rocky here but they do have a sandy beach)

Aww thank you for sharing a picture of yours. Such beautiful fish! Yours look very happy with all the plants and caves. Ours also are super skittish also. Oddly enough though I seem them all the time in the front of the tank swimming in dance like patterns together. We made our dining space a tank area with a couch so we can watch them lol. I think I will probably wait to increase the Sterbai unless my sisters plans change. Appreciate your story and help!

I had an upside down catfish for a year and he was great; got into a really nasty fight with a bn pleco when the pleco tried to steel food he was eating; so there is that aspect. The one i had was solo but my understanding is they do better in a group. He was really outgoing and friendly fellow as long as you didn't try to take the food out from under him. I had mine in a 40b and i presume a group of 4 or 5 would do well but i'd add some slanted driftwood so they have places they can hang out - mango wood or soemthing that have lots of branches. Also you should cover the heater - mine would spend a lot of time resting on the heater and there is the potential for them to get burned.

I have been watching her with cory's and wondering if she is chasing them. She will dart quickly in their direction but then stop and go swimming merrily away. She certainly is more assertive than the corys. My husbands tank only has a few spots for her though, so I think that is part of the problem. I've got 7 medium-large size spiderwood pieces with lots of branches soaking in my breeder. I also plan to be heavily planted with swords, floaters, anubias, lilys and few tall stems. My goal is to have tons of hiding spots for all species and maximum floor space for sand sifting.

Appreciate the tip about the heater. Mine is currently attached vertical next to the filter. Do you think that is still problematic?

 

[tinylostwine]

Aww thank you for sharing a picture of yours. Such beautiful fish! Yours look very happy with all the plants and caves. Ours also are super skittish also. Oddly enough though I seem them all the time in the front of the tank swimming in dance like patterns together. We made our dining space a tank area with a couch so we can watch them lol. I think I will probably wait to increase the Sterbai unless my sisters plans change. Appreciate your story and help!

I have been watching her with cory's and wondering if she is chasing them. She will dart quickly in their direction but then stop and go swimming merrily away. She certainly is more assertive than the corys. My husbands tank only has a few spots for her though, so I think that is part of the problem. I've got 7 medium-large size spiderwood pieces with lots of branches soaking in my breeder. I also plan to be heavily planted with swords, floaters, anubias, lilys and few tall stems. My goal is to have tons of hiding spots for all species and maximum floor space for sand sifting.

Appreciate the tip about the heater. Mine is currently attached vertical next to the filter. Do you think that is still problematic?

I don't think the filter is an issue as long as they can't get trapped by it; they probably like the current it generates. A bit depends on your filter design. I use a small canister filter and put sponges over the intake and the fishes would spend a lot time there poking at the sponge looking for food. If you ahve a hob it might be more problematic as the fishes can jump into it - i had a sword tail that ended up trapped in my hob for 2 weeks because i couldn't find her and couldnt' believe she could be up there (she was a large full grown female). I really liked the upside down i had but every fish has a different personality - also sex makes a difference on how they behave (no clue if mine was female or male).

These days on my small aquariums i use matten filter and large one sumps so i only have one aquarium left with a canister filter - on my 40 i have a nice corner matten filter (a mattern filter is just a sponge with a little space behind it and a air driven thingy to push water to other side). Think giant sponge filter. I put my heaters behind the sponge so fishes can't reach them.

 

[sharkbaithoohah]

I don't think the filter is an issue as long as they can't get trapped by it; they probably like the current it generates. A bit depends on your filter design. I use a small canister filter and put sponges over the intake and the fishes would spend a lot time there poking at the sponge looking for food. If you ahve a hob it might be more problematic as the fishes can jump into it - i had a sword tail that ended up trapped in my hob for 2 weeks because i couldn't find her and couldnt' believe she could be up there (she was a large full grown female). I really liked the upside down i had but every fish has a different personality - also sex makes a difference on how they behave (no clue if mine was female or male).

These days on my small aquariums i use matten filter and large one sumps so i only have one aquarium left with a canister filter - on my 40 i have a nice corner matten filter (a mattern filter is just a sponge with a little space behind it and a air driven thingy to push water to other side). Think giant sponge filter. I put my heaters behind the sponge so fishes can't reach them.

I have a HOB filter but floating plants that sort of block it out from the top. You definitely gave me some important things to consider thank you! Also going to look in to the matten filter, that sounds like a smart design and easy way to solve potentional problems.

 

[BPSabelhaus]

"You were in a 4g dive with a corydora?"

"I was inverted, sir. It's basically an 8 gallon"