Are Cardinal Tetras Aggressive?

[monkeyhanger]

We've had some issues with Neon Tetras dying (4 out of 9 dead/dying with NTD symptoms and with fungal infection, 2 active ones with a bit of fungal, 3 totally untouched) over the last week. Decided to replace the dead ones with cardinals when everything clears up, as the Cardinals and Neons are supposedly ok to mix and can shoal together (from what i've read)

Doh! Just finished watching the footie (poor newcastle fan!) to find our lass has come in with a bag of 5 Cardinals to replace the neons. Told her on Saturday that we were going to wait for 2 weeks of normality before getting more fish.

As she'd bought them and the shop was now closed, had no choice but to put them in. They mixed with the neons straight way, seemed sociable with each other and shoaling together.

2 of our 5 remaining neons were slightly affected by the illness that killed the other 4 (small amonts of greying/fluffiness), one of them more so than the other. 3 of the cardinals took it in turns to head-butt the most sickly neon. It was just floating aimlessly so I had to remove it.

From experience, does anyone know if this was a pure act of aggression from the cardinals, or whether they were trying to eliminate the neon because it was sick and therefore a threat to their own wellbeing?

 

[keenonfish]

Have you treated the illness at all? Sounds like it could be Columnaris if so you need to go to the emergency section right away and post all your stats (use form to give idea) as if there is still any disease in the tank it could very quickly wipe out the rest of your stock. It is a terrible disease and you have little time to act once the symptoms set in. NTD is generally not very common but can effect any fish bit just Neons and is not, as far as I am aware curable.

Please do as above and someone with experience will help you soon

edit *didn't realise this is the emergency section

ok someone will ask you for all stats so you need as much as the following possible...


When posting a request for help can you please include the following info

1. Water parameters. (ammonia, nitrate, nitrite, PH, temp', Hardness etc)
2. A full description of the fishes symptoms.
3. How often you do water changes and how much.
4. Any chemicals and treatments you add to the water.
5. What tank mates are in the tank.
6. Tank size.
7. Finally Have you recently added any new fish?

You may cut and paste the template below and submit in your post:

Request Help

Tank size:
pH:
ammonia:
nitrite:
nitrate:
kH:
gH:
tank temp:

Fish Symptoms (include full description including lesion, color, location, fish behavior):

Volume and Frequency of water changes:

Chemical Additives or Media in your tank:

Tank inhabitants:

Recent additions to your tank (living or decoration):

Exposure to chemicals:

Digital photo (include if possible):

 

[monkeyhanger]

Have you treated the illness at all? Sounds like it could be Columnaris if so you need to go to the emergency section right away and post all your stats (use form to give idea) as if there is still any disease in the tank it could very quickly wipe out the rest of your stock. It is a terrible disease and you have little time to act once the symptoms set in. NTD is generally not very common but can effect any fish bit just Neons and is not, as far as I am aware curable.

Please do as above and someone with experience will help you soon

edit *didn't realise this is the emergency section

ok someone will ask you for all stats so you need as much as the following possible...


When posting a request for help can you please include the following info

1. Water parameters. (ammonia, nitrate, nitrite, PH, temp', Hardness etc)
2. A full description of the fishes symptoms.
3. How often you do water changes and how much.
4. Any chemicals and treatments you add to the water.
5. What tank mates are in the tank.
6. Tank size.
7. Finally Have you recently added any new fish?

You may cut and paste the template below and submit in your post:

Request Help

Tank size:
pH:
ammonia:
nitrite:
nitrate:
kH:
gH:
tank temp:

Fish Symptoms (include full description including lesion, color, location, fish behavior):

Volume and Frequency of water changes:

Chemical Additives or Media in your tank:

Tank inhabitants:

Recent additions to your tank (living or decoration):

Exposure to chemicals:

Digital photo (include if possible):

Everything's been documented in the post "dead and vanished neons" within the emergency section. We seem to be over it now - but my lass got the Cardinals when she should've waited.

I'm still adding meds at low levels until i'm sure it's gone.

Current stock is

4 neons
5 cardinals
4 platys
1 betta
6 glass tetra
4 Cory Sterbai

Water parameters are

Ammonia = 0ppm
Nitrite = 0ppm
Nitrate = Less than 5ppm
pH = 7.4

Steady at those levels for 6 weeks.

140 Litre tank, with live plants.

Neons are oldest inhabitants at 13 weeks
Platys 9 weeks
Sterbai 5 weeks
Betta 4 weeks
Glass Tetras 3 weeks
Cardinals are brand new

 

[monkeyhanger]

Anyone have any comments about the general behaviour of the cardinals with the neons, as stated in the first post?

It was the reason behind the cardinals attacks on the slightly sick neon that I was trying to determine.

 

[nmonks]

Let me be honest about neons: in the UK at least, and likely elsewhere, either don't get them, or buy twice as many as you want! The neons in the trade are often of hopelessly poor quality, and when you see them in the shops, the symptoms of Neon Tetra Disease are often obvious. Since this disease (or diseases, there may be two "flavours") isn't/aren't curable, and is/are highly contagious as well, once one's got Neon Tetra Disease, they've pretty well all got it.

There are some things about neons you should know. For a start, they come from relatively cool water. If you keep them above 24 C, you're stressing them. They're also highly sensitive to poor water quality, and some forms of Neon Tetra Disease may be opportunistic bacterial infections that overwhelm the poor neon when kept inappropriately. Though bred to a low price point, the reality may well be that these are difficult fish not for beginners or even casual aquarists who otherwise know what they're doing.

Cardinals are a good bit hardier, provided you have soft, acidic, and rather warm water. Since there's not much overlap between the temperature cardinals want and the temperature neons want, you can't mix them and expect both to thrive. It's one or the other. Cardinals simply don't do well in "liquid rock" hard water, and aren't worth buying for such conditions.

There is absolutely no reason to assume that one species would attack the other because of some perceived threat to their happiness. Fish don't work that way. But having said that, both are schooling species, and it is absolutely typical for schooling species to be [a] bullies and psychotic when kept in insufficient numbers. In small groups there's really no reason to expect any schooling fish to behave, and within small groups it may well be possible for the larger cardinals to throw their weight around and try to bully the smaller neons. That said, both species are somewhat cannibalistic and will turn on dying/dead specimens of their own kind.

Really, I recommend people avoid neons like the plague. They're just not worth it. As for cardinals, provided you buy twenty or more, and keep them in warm, soft, acid water, they're pretty good. Keep them in smaller groups, or in the wrong water chemistry, and you're taking a gamble.

Cheers, Neale