Updates after being away over the holidays. The good news is that I don't see any worms hanging out of my fish. It would appear that the fenbendazole worked. I need to re-treat the tank soon (it's recommended that you re-treat after two weeks) to kill any larvae that have re-infected the fish. Still, it looks good.
On the other hand, I lost a lot of fish. I came home last night to a house that stank of rotting fish. In the main tank, I lost both angels, my fighter, and all of my neons. I lost at least one Macropodus, probably more. I haven't determined what happened to the corys and the kuhli loaches - I saw one kuhli loach, all three of the panda corys, and several of the others. I see one Otocinclus, but I'm not sure about the second one. The water was horrible when I got home - I'm impressed that any fish survived such polluted water.
In the plant tank, I see a lot of shrimp, two Otocinclus and a few of the pygmy corys. I haven't seen many pygmy corys,; I'm hopeful, but concerned. The tank had very heavy algal growth - probably a consequence of having the lights on 24 hours a day for almost two weeks.
I haven't taken a good look at the Macropodus tank. There are at least a dozen fish in there, but it's very messy and overgrown. I haven't yet tried to tackle that one.
Showing posts with label Angelfish. Show all posts
Showing posts with label Angelfish. Show all posts
Thursday, 3 January 2008
Thursday, 20 December 2007
Timeline of infection
A parasitic nematode like Camallanus needs to get into the aquarium from somewhere. I've been thinking about possible paths of infection. According to Levsen and Berland (2001) Camallanus cotti takes 11 days to fully develop in its copeopd host, and then another 34-42 days to develop after it is ingested by a fish host. Presumably the adult feeds for at least a few days before it extrudes from the anus of the fish and starts releasing larvae of its own. Levsen (2001) found that it took a minimum of 62 days and a maximum of 110 days for visible signs of the parasite in a system with monoxeny - direct (fish to fish) infection. Since I first saw signs on the worms in mid-December, they became infected somewhere between early September and early November. That said, I first noticed the worms last weekend, and once I looked there were worming hanging out of several Macropodus.
In that time period I bought (and didn't adequately quarantine) quite a few fish. The fighter is an unlikely culprit - not only did we buy him too recently, he also shows no signs of infection. The pygmy corys are also unlikely, since they have never been in the main tank. On the other hand, the plant tank has a population of copepods, so I would only have to introduce the copepods, not actually any fish. It's reasonable that Camallanus was introduced with infected copepods that came with the Java moss. The timeline is reasonable - about 55 days. I also transferred a couple larger corys from the plant tank to the main tank, and an Otocinclus. They are also potential sources of infection.
There are, of course, other possibilities. I bought three batches of neon tetras this Fall, and had remarkably high mortality. I also bought some ghost shrimp. The ghost shrimp themselves are unlikely vectors - I have not read about Camallanus infecting shrimp, although there's a slight chance that they were using them as secondary hosts. The neons, on the other hand, are another story.
I bought my first batch of neons back in early September. Four of the five died within two days, and that was followed by a wave of mortality: a fighter, two Angels, two platies and a couple Macropodus. It seems pretty obvious that they weren't the ""cleanest" of fish. The extra burden of Camallanus infection could be blamed for the death of the neons (if you're already feeding parasitic worms, you have fewer resources with which to handle stress), it seems unlikely that transmission of the Camallanus larvae could have resulted in such rapid mortality among the other fish.
While I initially blamed the pet store, the deaths of the other fish led me to wonder whether something had gone wrong with my water, and that the timing might have been coincidental. Anyway, the sole survivor remained in the tank, seemingly healthy, but with a shrunken abdomen (which was always a cause for concern). He died a couple months later, after I bought some more neons to keep him company.
I'm most inclined to blame the neons (or more specifically, the one neon). And while I could do a lot to improve my quarantine procedures, segregating new fish for 2 to 4 months just isn't something I can do at present. While I hate the idea of medicating new fish as a precautionary measure, I can see why people would do it.
In that time period I bought (and didn't adequately quarantine) quite a few fish. The fighter is an unlikely culprit - not only did we buy him too recently, he also shows no signs of infection. The pygmy corys are also unlikely, since they have never been in the main tank. On the other hand, the plant tank has a population of copepods, so I would only have to introduce the copepods, not actually any fish. It's reasonable that Camallanus was introduced with infected copepods that came with the Java moss. The timeline is reasonable - about 55 days. I also transferred a couple larger corys from the plant tank to the main tank, and an Otocinclus. They are also potential sources of infection.
There are, of course, other possibilities. I bought three batches of neon tetras this Fall, and had remarkably high mortality. I also bought some ghost shrimp. The ghost shrimp themselves are unlikely vectors - I have not read about Camallanus infecting shrimp, although there's a slight chance that they were using them as secondary hosts. The neons, on the other hand, are another story.
I bought my first batch of neons back in early September. Four of the five died within two days, and that was followed by a wave of mortality: a fighter, two Angels, two platies and a couple Macropodus. It seems pretty obvious that they weren't the ""cleanest" of fish. The extra burden of Camallanus infection could be blamed for the death of the neons (if you're already feeding parasitic worms, you have fewer resources with which to handle stress), it seems unlikely that transmission of the Camallanus larvae could have resulted in such rapid mortality among the other fish.
While I initially blamed the pet store, the deaths of the other fish led me to wonder whether something had gone wrong with my water, and that the timing might have been coincidental. Anyway, the sole survivor remained in the tank, seemingly healthy, but with a shrunken abdomen (which was always a cause for concern). He died a couple months later, after I bought some more neons to keep him company.
I'm most inclined to blame the neons (or more specifically, the one neon). And while I could do a lot to improve my quarantine procedures, segregating new fish for 2 to 4 months just isn't something I can do at present. While I hate the idea of medicating new fish as a precautionary measure, I can see why people would do it.
- Levsen, A. (2001). Transmission Ecology and Larval Behaviour of Camallanus cotti (Nematoda, Camallanidae) Under Aquarium Conditions . Aquarium Sciences and Conservation, 3(4), 315-325. DOI: 10.1023/A:1013137801600
- Levsen, A., Berland, B. (2002). The development and morphogenesis of Camallanus cotti Fujita, 1927 (Nematoda: Camallanidae), with notes on its phylogeny and definitive host range. Systematic Parasitology, 53(1), 29-37. DOI: 10.1023/A:1019955917509
Wednesday, 24 October 2007
Breeding Angelfish?
Two of my four angels died in the aftermath of my neon tetra fiasco. Since I lost one member of each "pair" of angels, I figured that my chances of breeding them was pretty close to nil. However, the two surviving angels are now behaving like they intend to breed.
Over the last week or so, the angels became very aggressive with one-another. That was nothing new - when there were four fish, they fought over the tank. One pair claimed the central half of the tank, and forced the other pair to occupy the ends of the tank. But this behaviour was different - one fish would attack, but the other would stand its ground, but not fight back. More tellingly, they have taken to cleaning Echinodorus leaves. After reading Bill Dawes FAQ on breeding angels, it seems pretty likely that they are attempting to spawn.
Over the last week or so, the angels became very aggressive with one-another. That was nothing new - when there were four fish, they fought over the tank. One pair claimed the central half of the tank, and forced the other pair to occupy the ends of the tank. But this behaviour was different - one fish would attack, but the other would stand its ground, but not fight back. More tellingly, they have taken to cleaning Echinodorus leaves. After reading Bill Dawes FAQ on breeding angels, it seems pretty likely that they are attempting to spawn.
Friday, 14 September 2007
Hunting
I think it's pretty safe to say that the best hunters I have had are Angels. They are probably the most intelligent fish I have had, and seem able to plan their moves beyond the most immediate. Fighters, on the other hand, don't strike me as very good hunters.
I had a male fighter in a tank with 30-40 Macropodus fry for about a week (see here). Remarkably, when I finally took him out of the tank, there were still several fry left. It may have been that he was in breeding mode, and was less prone to eat little creatures swimming around his nest (although I saw him eat some of them right under his nest), but having watched him hunt, I think he was just an inefficient hunter (the female fighter, who was in the tank with him for certain periods of time, seemed to be better at it, thought still not an expert).
As I could tell (based on my rather limited observations) fighters hunt by swimming up to a potential prey item, and then snapping at it. If they prey item (Macropodus fry, in this case) can see them, they can get away. The fighter won't give chase, so it's possible to escape. Angels, on the other hand, seem to give chase and corner their prey - when the angels went after the neons, they gave chase and cornered their prey. Of course, they went at the fish as a group, which is something a more solitary fish like a fighter is unable ot do. But still, even single angels strike me as more efficient hunters. I suppose it reflects their prey source. Fighters aren't good at swimming fast - their long fins aside (something their ancestors wouldn't have had), they just aren't the sort of sustained swimmers that angelfish are. They probably depend more on prey that is either unable to see them (mosquito larvae?) or on lying in wait. Angels, on the other hand, are better swimmers. Given their reaction to the neons, I'm pretty sure that they are piscivores in nature.
I had a male fighter in a tank with 30-40 Macropodus fry for about a week (see here). Remarkably, when I finally took him out of the tank, there were still several fry left. It may have been that he was in breeding mode, and was less prone to eat little creatures swimming around his nest (although I saw him eat some of them right under his nest), but having watched him hunt, I think he was just an inefficient hunter (the female fighter, who was in the tank with him for certain periods of time, seemed to be better at it, thought still not an expert).
As I could tell (based on my rather limited observations) fighters hunt by swimming up to a potential prey item, and then snapping at it. If they prey item (Macropodus fry, in this case) can see them, they can get away. The fighter won't give chase, so it's possible to escape. Angels, on the other hand, seem to give chase and corner their prey - when the angels went after the neons, they gave chase and cornered their prey. Of course, they went at the fish as a group, which is something a more solitary fish like a fighter is unable ot do. But still, even single angels strike me as more efficient hunters. I suppose it reflects their prey source. Fighters aren't good at swimming fast - their long fins aside (something their ancestors wouldn't have had), they just aren't the sort of sustained swimmers that angelfish are. They probably depend more on prey that is either unable to see them (mosquito larvae?) or on lying in wait. Angels, on the other hand, are better swimmers. Given their reaction to the neons, I'm pretty sure that they are piscivores in nature.
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