rubadudbdub
Member
- Joined
- 27 Oct 2015
- Messages
- 143
Firstly sorry for the long post. I'm hoping some cory or fish heath enthusiasts will make it to the end and offer some advice. I have had an issue with my panda corydoras for a few months. I started with a small group of adults which then laid eggs in the tank and a steady trickle of fry have survived since May 2020 bringing the group up to about 12. The odd youngster (2 over 6 months) seemed to struggle, stayed rather thin and did not grow as well. Typically they then go very pale, look lethargic and disappear in the fairly densely planted tank. In the last month one of the young adults has done the same and then one of the original parents. Both of the latter had lost some of their whiskers, with the parent looking noticeably thinner. I moved these two into a bare tank with mature sponge filter and initially treated with methylene blue/malachite green, then an anti fluke/wormer (flubendazole 10mg/ml treats 50 litres). The young adult died, the older one is looking a little brighter, less lethargic and feeding better. Last Sunday was the 3rd weekly dose of flubendazole.
Rightly or wrongly, I'm leaning towards it being some kind of intestinal parasite. There is nothing visible externally, I rarely see the fish scratch, although they do from time to time.
Around 14 months ago I put a group of 6+5 pygmae corys in the same tank from TA aquaculture and Sweet Knowle, both of whom are good shops that quarantine. 2 pygmaes were similar to the pandas above, quite pale and slower than the rest. This pair also had peculiar behaviour, they were far bolder and would hang vertically completely still above the substrate. It reminded me of a parasitology lecture at uni where parasites would modify host behaviour to increase predation risk as part of their life cycle. I decided to treat the whole group but after 2 hours of chasing only caught the 2 pale slow fish, both of whom died. No problems with the rest of the pygmaes since.
Tank: juwel Rio 125, eheim pro2 external, water changes 50% every 3 weeks.
Substrate: 2/3 of the tank has a 2" substrate with lots of crypts/vallis nana with gravel over JBL aquabasis, 1/3 unipac samoa sand shallow covering ~ 1.5cm - its rarely got much in it when I clean it. There is some half buried redmoor root that the pygmaes live under, making catching them extremely difficult. I usually have a fairly thick covering of floating plants.
Fish: 8-9 pygmaes, 6 panda corys adult/young (I've moved some out now) with a 2-3 tiny fry, 8 rummy noses and a few aging endlers. Over the last few months I've been raising Nothobranchius and Fundulpanchax fry in a Ziss breeding box in the tank without noticeable losses. Also a colony of cherry shrimp and 3 large amanos.
If I'm honest I don't really know what I'm treating but the steady trickle of sick fish is making me wonder if I should uproot all the redmoor half buried in the substrate, trim the plants, catch the corys and treat them all even if those remaining look healthy for now. Parasite treatments seem not to be shrimp safe, otherwise i'd dose the tank. There was also ~7-8 months between the pale pygmae corys dying and the first panda fry looking pale and lethargic. So I accept there's a good chance the two issues are unrelated.
I associate lost cory whiskers with poor water quality. I have checked nitrite and its zero, although i could/should up water changes to fortnightly. The original spawning adults are still spawning this week, cory and fundulopanchax gardneri fry are happily growing, so my gut feeling is the water is OK. However, I did get caught out with some rich soft artemia feed from TA that a large group of cory fry (in another smaller tank set up with soil) hoovered up like sweets and caused a chronic low level of nitrite (lowest colour on the tetra kit) when I started chucking it in too liberally. This coincided with the extremely hot weather and I lost 20 ~2cm cory fry, lesson learnt, don't over feed young fish. Even if i assume this tank was also over fed last summer, it is months past that now and I still have an issue, despite the other fish seeming ok and new fry appearing.
I'm interested in people's thoughts. Does the story sound like an internal parasite problem, if so which are the treatments to go for and what would you do? What are the more common corydoras pathogens in people's experience, as common things are common? I have a new rio 240 that I've just set up that is maturing with some goldfish and the plan was to build up to large shoal (30-40) of pygmae corys along with the pandas I have currently. I am loath to seed a problem into a new tank, and have an opportunity to treat fish as i move them to the new tank. If I can decide whats wrong with them and what treatment to offer. Any advice or critique is very welcome. Thanks
Rightly or wrongly, I'm leaning towards it being some kind of intestinal parasite. There is nothing visible externally, I rarely see the fish scratch, although they do from time to time.
Around 14 months ago I put a group of 6+5 pygmae corys in the same tank from TA aquaculture and Sweet Knowle, both of whom are good shops that quarantine. 2 pygmaes were similar to the pandas above, quite pale and slower than the rest. This pair also had peculiar behaviour, they were far bolder and would hang vertically completely still above the substrate. It reminded me of a parasitology lecture at uni where parasites would modify host behaviour to increase predation risk as part of their life cycle. I decided to treat the whole group but after 2 hours of chasing only caught the 2 pale slow fish, both of whom died. No problems with the rest of the pygmaes since.
Tank: juwel Rio 125, eheim pro2 external, water changes 50% every 3 weeks.
Substrate: 2/3 of the tank has a 2" substrate with lots of crypts/vallis nana with gravel over JBL aquabasis, 1/3 unipac samoa sand shallow covering ~ 1.5cm - its rarely got much in it when I clean it. There is some half buried redmoor root that the pygmaes live under, making catching them extremely difficult. I usually have a fairly thick covering of floating plants.
Fish: 8-9 pygmaes, 6 panda corys adult/young (I've moved some out now) with a 2-3 tiny fry, 8 rummy noses and a few aging endlers. Over the last few months I've been raising Nothobranchius and Fundulpanchax fry in a Ziss breeding box in the tank without noticeable losses. Also a colony of cherry shrimp and 3 large amanos.
If I'm honest I don't really know what I'm treating but the steady trickle of sick fish is making me wonder if I should uproot all the redmoor half buried in the substrate, trim the plants, catch the corys and treat them all even if those remaining look healthy for now. Parasite treatments seem not to be shrimp safe, otherwise i'd dose the tank. There was also ~7-8 months between the pale pygmae corys dying and the first panda fry looking pale and lethargic. So I accept there's a good chance the two issues are unrelated.
I associate lost cory whiskers with poor water quality. I have checked nitrite and its zero, although i could/should up water changes to fortnightly. The original spawning adults are still spawning this week, cory and fundulopanchax gardneri fry are happily growing, so my gut feeling is the water is OK. However, I did get caught out with some rich soft artemia feed from TA that a large group of cory fry (in another smaller tank set up with soil) hoovered up like sweets and caused a chronic low level of nitrite (lowest colour on the tetra kit) when I started chucking it in too liberally. This coincided with the extremely hot weather and I lost 20 ~2cm cory fry, lesson learnt, don't over feed young fish. Even if i assume this tank was also over fed last summer, it is months past that now and I still have an issue, despite the other fish seeming ok and new fry appearing.
I'm interested in people's thoughts. Does the story sound like an internal parasite problem, if so which are the treatments to go for and what would you do? What are the more common corydoras pathogens in people's experience, as common things are common? I have a new rio 240 that I've just set up that is maturing with some goldfish and the plan was to build up to large shoal (30-40) of pygmae corys along with the pandas I have currently. I am loath to seed a problem into a new tank, and have an opportunity to treat fish as i move them to the new tank. If I can decide whats wrong with them and what treatment to offer. Any advice or critique is very welcome. Thanks