How many corys for a 55 gal (more info in thread)

Eridinus

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Hi Guys.

Got a 55 gal (101cm x 41cm x 50cm) going at the moment, currently being occupied by 8 bronze corys and 3 adolfi corys.

I want to increase the amount of adolfi up to a minimum of 6 so they feel safe, but I also don't want to overcrowd the bottom level of my tank.

So how many corys can I realistically have?
 
From the perspective of the cories alone (i.e., not considering/knowing upper fish here) you could easily have 50+ in total. I had a 70g with 50, and these will be going into my 40g after I move this week. Cories live in groups of hundreds, so from their point of view there can never really be too many!

You should have some chunks of wood, as they like hiding places to feel safer, and enjoy browsing all the surfaces.
 
From the perspective of the cories alone (i.e., not considering/knowing upper fish here) you could easily have 50+ in total. I had a 70g with 50, and these will be going into my 40g after I move this week. Cories live in groups of hundreds, so from their point of view there can never really be too many!

You should have some chunks of wood, as they like hiding places to feel safer, and enjoy browsing all the surfaces.
Okay thanks!

To be honest I am probably looking at getting some praecox rainbows (6 min) for the upper level, and then possibly some psuedomugil luminatus. I'll definitely look to get 3 more adolfis then!

Would you say that with all the above I could also get a trio of ottos? I have let the algae grow a fair amount so that I could put in either some ottos or a single/trio of SAE (Crossocheilus siamensis).

I know you said on another thread about not having SAEs due to the current, but the way I have the flow going at the moment there is a fair amount of movement in the water.
 
To be honest I am probably looking at getting some praecox rainbows (6 min) for the upper level, and then possibly some psuedomugil luminatus. I'll definitely look to get 3 more adolfis then!

My comment on upper fish was primarily one of the biological load in the tank, but there are no issues here. I would suggest more of the praecox and two females per male. The Psuedomugil luminatus might get lost in this large a tank and with the out-competing praecox, Colin can comment on that. And these small fish may not appreciate water currents, again Colin can advise.

What algae species? The SAE are not efficient algae eaters except for brush/beard, plus they should have five or six, they get large...I would not even consider them with the rainbows. And not with cories. Otos...they will eat common green algae or diatoms, but nothing else.

I would increase the cories significantly. By adolfoi do you actually mean Corydoras adolfoi, or the more often seen C. duplicareus which is usually labelled "adolfoi" as it is better known? Whichever, a larger group is always better for these, I have ten C. duplicareus in with my 50 cories and they are quite striking and frequently in groups of their own species.
 
My comment on upper fish was primarily one of the biological load in the tank, but there are no issues here. I would suggest more of the praecox and two females per male. The Psuedomugil luminatus might get lost in this large a tank and with the out-competing praecox, Colin can comment on that. And these small fish may not appreciate water currents, again Colin can advise.

What algae species? The SAE are not efficient algae eaters except for brush/beard, plus they should have five or six, they get large...I would not even consider them with the rainbows. And not with cories. Otos...they will eat common green algae or diatoms, but nothing else.

I would increase the cories significantly. By adolfoi do you actually mean Corydoras adolfoi, or the more often seen C. duplicareus which is usually labelled "adolfoi" as it is better known? Whichever, a larger group is always better for these, I have ten C. duplicareus in with my 50 cories and they are quite striking and frequently in groups of their own species.
I think I will have to finally say no to Crossocheilus siamensis then. I'll get some Otos this weekend as well as maybe some Corydoras pygmaeus as I do love my corys! Then the week after I will look to get either 1 or 2 upper level species. Don't want to accidentally start a cycle.

They're definitely Corydoras adolfoi, though yesterday I picked up 3 more and 1 seems to have black in his dorsal fin, leading me to believe he is a duplicareus. This morning I woke to see all 6 of them sat in a line, so at least they seem to stick together.
 
I'll get some Otos this weekend as well as maybe some Corydoras pygmaeus as I do love my corys!

I would wait on the otos until the tank is well established with some common algae [maybe it already is?]. Otos are to the point of starvation when we acquire them and without a good amount of natural algae they often die soon.

Corydoras pygmaeus do better in smaller tanks. Mixed in with the larger cories never seems to quite work, at least not in my experience. Not that the larger pick on them, no Corydoras species does this, but the pygmies seem to get lost and not do so well. My group in a 10g spawn regularly and have for several years now. They need sand and cooler temperatures, though this applies to all cories anyway, but with the pygmy it is mandatory.

They're definitely Corydoras adolfoi, though yesterday I picked up 3 more and 1 seems to have black in his dorsal fin, leading me to believe he is a duplicareus. This morning I woke to see all 6 of them sat in a line, so at least they seem to stick together.

Photos would help with ID, sort of. Externally, the black dorso-lateral stripe on C. adolfoi is usually much narrower than on C. duplicareus though sometimes this is not that easy to see, but generally both this band and the eye band are much broader. On some of my fish the lateral band extends more than half-way down the sides of the fish. The black may extend up into the dorsal, to varying degrees depending upoin individual fish--on some of mine the entire fin is coal black.

The orange post-orbital fleck on C. dupiocareus is a much brighter orange when compared to C. adolfoi, (though this too is not always so obvious depending upon the condition of the fish) and it remains brightly coloured as the fish matures which is apparently not the case with C. adolfoi, usually. The only absolute ID is the pectoral fin spine ray, which is smooth on C. adolfoi and slightly serrated on C. duplicareus but this requires viewing under a microscope to see clearly. Having said that, it is very rare to see true C. adolfoi these days, as they are just not as brilliant in their pattern and colour by comparison; the "adolfoi" name is almost always given to C. duplicareus by exporters/importers at least in NA.

There are other closely related species too; C. imitator (identical in pattern/colour to C. adolfoi) and C. serratus (identical to C. duplicareus) but both of these have the long snout as opposed to the blunt snout so that is pretty obvious. Some 12 new species were discovered during the 1980's and 1990's, each endemic to specific southerly-flowing tributaries of the upper Rio Negro, and having very similar cryptic (camouflaging) colour patterns. When viewed from above in the habitats, the colour pattern of all these fish cause them to blend in with the twigs and branches that litter the buff-coloured sandy streambeds. The patterns include a buff-coloured body with a black dorsolateral band (that may only be partial on some species), a black eye band, and an orange post orbital fleck in the shape of a "V" when viewed from above, the intensity of which varies between the species.
 
I would wait on the otos until the tank is well established with some common algae [maybe it already is?]. Otos are to the point of starvation when we acquire them and without a good amount of natural algae they often die soon.

Corydoras pygmaeus do better in smaller tanks. Mixed in with the larger cories never seems to quite work, at least not in my experience. Not that the larger pick on them, no Corydoras species does this, but the pygmies seem to get lost and not do so well. My group in a 10g spawn regularly and have for several years now. They need sand and cooler temperatures, though this applies to all cories anyway, but with the pygmy it is mandatory.



Photos would help with ID, sort of. Externally, the black dorso-lateral stripe on C. adolfoi is usually much narrower than on C. duplicareus though sometimes this is not that easy to see, but generally both this band and the eye band are much broader. On some of my fish the lateral band extends more than half-way down the sides of the fish. The black may extend up into the dorsal, to varying degrees depending upoin individual fish--on some of mine the entire fin is coal black.

The orange post-orbital fleck on C. dupiocareus is a much brighter orange when compared to C. adolfoi, (though this too is not always so obvious depending upon the condition of the fish) and it remains brightly coloured as the fish matures which is apparently not the case with C. adolfoi, usually. The only absolute ID is the pectoral fin spine ray, which is smooth on C. adolfoi and slightly serrated on C. duplicareus but this requires viewing under a microscope to see clearly. Having said that, it is very rare to see true C. adolfoi these days, as they are just not as brilliant in their pattern and colour by comparison; the "adolfoi" name is almost always given to C. duplicareus by exporters/importers at least in NA.

There are other closely related species too; C. imitator (identical in pattern/colour to C. adolfoi) and C. serratus (identical to C. duplicareus) but both of these have the long snout as opposed to the blunt snout so that is pretty obvious. Some 12 new species were discovered during the 1980's and 1990's, each endemic to specific southerly-flowing tributaries of the upper Rio Negro, and having very similar cryptic (camouflaging) colour patterns. When viewed from above in the habitats, the colour pattern of all these fish cause them to blend in with the twigs and branches that litter the buff-coloured sandy streambeds. The patterns include a buff-coloured body with a black dorsolateral band (that may only be partial on some species), a black eye band, and an orange post orbital fleck in the shape of a "V" when viewed from above, the intensity of which varies between the species.

Here is an imgur link for some pictures today. I can get some more but the run and hide if I go too close!
https://imgur.com/gallery/SU77Z3b
I believe the darker 2 might be a different species.
 
Here is an imgur link for some pictures today. I can get some more but the run and hide if I go too close!
https://imgur.com/gallery/SU77Z3b
I believe the darker 2 might be a different species.

If by darker two you mean the two side-by-side cories in the second photo down, I would say those are C. duplicareus. As for the rest, they are likely also C. duplicareus. I have reasons aside from appearance to think this.

If these all came from the same shipment to/in the one store, it is very unlikely they are a mixed species lot. These fish will be wild caught, and their natural habitats do not overlap, as I mentioned in my previous post. Each is endemic (= found no where else that we know of) to a specific northern tributary (several parallel streams) of the Rio Negro in Brazil. So mixing such species is highly unlikely unless the exporter was extremely careless. There is, as I mentioned, variability in the pattern/colour of individual fish within these species.

An interesting observation was made by Dr. David Sands during his expeditions to these streams in the 1980's and early 1990's (he discovered most of the 12 species and described them scientifically (except for C. adolfoi and C. imitator which were described respectively by Dr. Warren Burgess [Burgess 1982] and Drs. Nijssen and Isbrucker [Nijssen & Isbrucker 1983] prior to Sands' work for his PhD in ichthyology). After discovering that each stream had a distinct endemic species which all shared a basic mimicry, he noted that the fish never left their respective stream. In other words, one might think that a fish could easily swim into the Rio Negro, remaining along the bank, and then up the neighbouring stream, and thus mingle. But they never do, which is why each stream has a distinct species that evolved within that stream. Dr. Sands suggested that the difference in pH and/or temperature of the Rio Negro from the tributaries could form a chemical barrier to the fish, one which they will not cross.

This is an interesting observation for another reason. Aquarists frequently suggest that a species is able to somehow adapt to differing water parameters with no issues. But if Dr. Sands is correct, this seems inaccurate. If the fish are "fenced in" to their stream by parameters, while having the easy opportunity to cross them, that should tell us something about the importance of matching wild parameters for healthy and less stressed fish.
 
If by darker two you mean the two side-by-side cories in the second photo down, I would say those are C. duplicareus. As for the rest, they are likely also C. duplicareus. I have reasons aside from appearance to think this.

If these all came from the same shipment to/in the one store, it is very unlikely they are a mixed species lot. These fish will be wild caught, and their natural habitats do not overlap, as I mentioned in my previous post. Each is endemic (= found no where else that we know of) to a specific northern tributary (several parallel streams) of the Rio Negro in Brazil. So mixing such species is highly unlikely unless the exporter was extremely careless. There is, as I mentioned, variability in the pattern/colour of individual fish within these species.

An interesting observation was made by Dr. David Sands during his expeditions to these streams in the 1980's and early 1990's (he discovered most of the 12 species and described them scientifically (except for C. adolfoi and C. imitator which were described respectively by Dr. Warren Burgess [Burgess 1982] and Drs. Nijssen and Isbrucker [Nijssen & Isbrucker 1983] prior to Sands' work for his PhD in ichthyology). After discovering that each stream had a distinct endemic species which all shared a basic mimicry, he noted that the fish never left their respective stream. In other words, one might think that a fish could easily swim into the Rio Negro, remaining along the bank, and then up the neighbouring stream, and thus mingle. But they never do, which is why each stream has a distinct species that evolved within that stream. Dr. Sands suggested that the difference in pH and/or temperature of the Rio Negro from the tributaries could form a chemical barrier to the fish, one which they will not cross.

This is an interesting observation for another reason. Aquarists frequently suggest that a species is able to somehow adapt to differing water parameters with no issues. But if Dr. Sands is correct, this seems inaccurate. If the fish are "fenced in" to their stream by parameters, while having the easy opportunity to cross them, that should tell us something about the importance of matching wild parameters for healthy and less stressed fish.

I was discussing this with the store owner and they said they're told they are adolfoi and that they get them in small. I thought this would be because they're hard to raise as fry and so they're shipped out as soon as they start maturing.

They were bought about 3 months apart, but from the same store. The newer ones all seem darker and with a lot more black on them.

I'll take your word about them being duplicareus, as it is extremely hard to tell. I might confront the store owner about this tbh and see if I can contact the supplier directly!

I'll be getting some Otos this weekend I think. There is a fair amount of algae in the tank now and I'm trying to keep it under control. One side of my tank is in sunlight for a large amount of the day and the algae is definitely growing faster in that area.
 
I'll be getting some Otos this weekend I think. There is a fair amount of algae in the tank now and I'm trying to keep it under control. One side of my tank is in sunlight for a large amount of the day and the algae is definitely growing faster in that area.

That should work. Sunlight directly on the tank is not advisable. Diffused daylight is OK, though that will promote algae too depending upon the intensity, duration, and the tank lighting itself.

I was discussing this with the store owner and they said they're told they are adolfoi and that they get them in small. I thought this would be because they're hard to raise as fry and so they're shipped out as soon as they start maturing.

They were bought about 3 months apart, but from the same store. The newer ones all seem darker and with a lot more black on them.

I'll take your word about them being duplicareus, as it is extremely hard to tell. I might confront the store owner about this tbh and see if I can contact the supplier directly!

Yes, see what he says. Just remember that he himself likely does not know the difference, and if the supplier has "adolfo cory" on their list, that is what he assumes they are. One of my local fish stores is privately run by a very knowledgeable lady whom I know quite well. She gets "aldolfo" cories two or three times a year, but after I examined them and pointed all this out, she now lists them as C. duplicareus ignoring the supplier's name. If the store you deal with orders direct from an exporter in Brazil, then they should be more accurate (not always, but usually). But if they are supplied through a commercial supplier outside of SA, the name may or may not have any relevance.

I am a member of Ian Fuller's cory group, and to date every "adolfoi" cory has been duplicareus with a very few exceptions. As I said, the duplicareus is more common notwithstanding the name confusion because it is a more attractive fish. David Sands is also a member of that group, and he has mentioned this himself. I wouldn't want to be the discoverer of a species that is being sold everywhere as another person's discovery!
 
That should work. Sunlight directly on the tank is not advisable. Diffused daylight is OK, though that will promote algae too depending upon the intensity, duration, and the tank lighting itself.



Yes, see what he says. Just remember that he himself likely does not know the difference, and if the supplier has "adolfo cory" on their list, that is what he assumes they are. One of my local fish stores is privately run by a very knowledgeable lady whom I know quite well. She gets "aldolfo" cories two or three times a year, but after I examined them and pointed all this out, she now lists them as C. duplicareus ignoring the supplier's name. If the store you deal with orders direct from an exporter in Brazil, then they should be more accurate (not always, but usually). But if they are supplied through a commercial supplier outside of SA, the name may or may not have any relevance.

I am a member of Ian Fuller's cory group, and to date every "adolfoi" cory has been duplicareus with a very few exceptions. As I said, the duplicareus is more common notwithstanding the name confusion because it is a more attractive fish. David Sands is also a member of that group, and he has mentioned this himself. I wouldn't want to be the discoverer of a species that is being sold everywhere as another person's discovery!

Thanks for the help!

The sunlight is through trees and direct only for an hour or so in the evening - I doubt at all in the Winter.

I'll hold off on the pygmaeus and probably just get some Otos and then a upper level species - then my tank is complete!
 

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