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.

Thursday 13 September 2007

The plant tank

About a week ago I moved the breeding pair of Macropodus out of the plant tank into the main tank. Above all else, I wanted them to just stop breeding, but I also was afraid that they were harassing the Otocinclus too much. But then, last weekend, on a whim we bought a couple of fighters. The male was the kind of colourless/golden fish you see from time to time these days, while the female was either the same of what we used to call "pearl". I figured the plant tank would make a good quarantine tank for them, although I was rather unhappy with the fact that this would mean that the Macropodus fry would become fish food. (Remarkably, several of them survived a week with the fighters).

Once I got them home I realised how small the female was. Still, given the size of the Macropodus female which had just bred in that tank, I wasn't going to rule out the possibility that she was ready to breed. Since the male built such an extensive nest, I let her out, but she was obviously uninterested. After a few hours I separated them again. Although I tried several times, I was unsuccessful. After a week of isolation I put them into the main tank. Maybe once she gets bigger I will give it another shot.

One big problem in the plant tank has been algal growth - a brownish, filamentous alga has gradually overgrown everything. Although I have removed a lot of it, the tank is still overrun with it. The two Otocinclus are either uninterested in this type of algae, or are simply overwhelmed, so I decided to buy a few more (I had wanted more than two when I bought these, but they only had two). And, since I've always wanted more corys, I bought a few of them as well - a new species, bringing my cory diversity to 4 species. I figured that since they root around on the bottom a lot more, they are likely to increase habitat heterogeneity. I'm hoping that this will have some effect on the algal overgrowth.

Friday 7 September 2007

Life and death

...luckily, without life in death.

Only one of the neons survived the weekend, which is really sad. It may have been a water-quality thing, I'm really not sure. Yesterday was truly tragic - my fighter, an angel and one of the platies all died. I was worried about the angel - it had a large gash on its side on Thursday morning. I was saddened, but not shocked, that it had died. But I'm not sure what killed the other fish. I did a major water change, but I'm not sure what else I could have done. But to little avail - now a second one of my angels is dead. It's really sad - they had grown into such nice big fish. I really wonder if the neons didn't bring some disease - why don't I quarantine new fish? You'd think I would have learned my lesson.

And in terms of life, the plant tank is full of Macropodus fry. I was hoping if I didn't feed them they wouldn't make it, but that isn't the case - there seems to be enough in there for them to eat...protists feeding on a healthy growth of algae and bacteria, I suppose.

Sunday 2 September 2007

Major changes

Saturday saw major upheavals in the world of my tanks.

I have wanted to reduce my platy population for months, and I am (obviously) overrun with Macropodus. For a long while now Linz promised a friend of hers both platies and Macropodus, but never remembered to drop them off. At last today we did just that. So we managed a substantial reduction in the population in the big tank. To celebrate that change, I went out and bought a few neon tetras. Hopefully they can handle the water conditions in there (the water is too hard and too alkaline for their liking, quite honestly) - I got 5, I'm hoping at least 3 survive. I'm hoping to keep five (or more) of them, but I really don't want fewer than 3.

When the angels caught sight of the neons it's obvious that they thought "food!" It was interesting to see them hunt - since all four of them moved in on the neons, they were kinda cornered. Luckily, the neons are really too big to be food for these angels, otherwise I would have had to get them out of there, quickly. I also moved the pair of Macropodus out of the plant tank into the main tank, where hopefully (a) they will stop breeding, and (b) they will grow up a bit (so I can find a good home for them). There are a few fry swimming around in the plant tank - you never know, with all that algae, there may be something for them to feed on in there. (I rather doubt the Otocinclus will hunt them).

In other news: I got new bulbs for the main tank. They are supposed to provide a better spectrum for plant growth. But the problem isn't only spectrum, it's total light availability. I also got a bag full of brine shrimp at the pet store today - fully grown brine shrimp. The fish loved them, especially the young Macropodus in the breeding tank.