Tuesday, 24 April 2007
Two of the original corys (sold to me as Corydoras aeneus, but clearly some other species).
One of these non-aeneus corys, with what I believe to be a true C. aeneus and a Panda cory (C. panda).
Monday, 23 April 2007
Saturday, 21 April 2007
Update: Turns out that I was wrong - there were actually quite a few fry in the nest. So will the male Macropodus eat the fry tomorrow? Should I leave the lights on tonight, so that he doesn't have to gather up so many fry (and end up "forgetting" to return them to the nest like last time), or should I switch the lights off and maybe give a few of the fry a chance to escape into the vegetation, which is now considerably more dense than it was last weekend (thanks to the plants I got from Bob)?
Update II: As of Monday morning, there are still quite a few fry around. Most of them have left the remnants of the nest and are on the underside of a large Echinodorus leaf that's floating on the surface of the tank. While the male Macropodus was still defending his portion of the tank, I couldn't tell if he was doing anything to "manage" the babies.
Friday, 20 April 2007
The first batch of fry are doing well, but the size disparity is getting larger. Most of the fry are "average" size - around 6 mm long. Several are smaller than average - around 4 mm long. And some are much larger than usual - over 10 mm long. [Update: The large ones are over 14 mm long]
It's the giants that are really interesting. Not only are they about twice the length of average fry, they are also 4 or 5 times the overall size of the average fry. At least one of them appears to be an air-breather (the labyrinth organ doesn't develop until the fry reach a certain size).
I'm interested in what the evolutionary strategy is here - or whether there is one. Floyd asked the question of whether there is some sort of advantage to having some fry remain stunted - perhaps as a food source for their larger siblings. While that might explain the smallest ones, it really doesn't explain the very large ones. There's a continuum of body sizes, but the very large fry seem to be outliers.
I have no idea whether this is typical or not. It's possible that these are truly unusual individuals, but it's also possible that this is a normal strategy for Macropodus. If so, it makes me wonder whether this could be viewed from the perspective of asynchronous germination in seeds. The normal way to interpret this would be as some sort of scramble competition - that the most successful strategy is to get big as quickly as possible, because faster growth allows you to outcompete your siblings and escape many predators (including your parents).
The problem with this interpretation is that getting big probably isn't a winning strategy for a territorial species living in a limited environment. Chances are, not only is reproduction only an issue for a fish that can claim a territory, it's also likely that reaching adult size is only an option if a territory becomes open (much like a tree colonising a gap). If that is the case, then growing large quickly doesn't guarantee success - it only represents one out of a range of strategies. It may be that some fish get big quickly to occupy an immediately available territory (if one exists) while other mature more slowly, with the "objective" of staying to occupy a territory that becomes available later on.
Wednesday, 18 April 2007
I ran the filter for a little while again yesterday - although the fry were still using the entire water column, I was a little concerned about oxygenation and BOD (biological oxygen demand). The fry are unlikely to be air breathers yet, and there's sure to be other decomposable material in the water. Added oxygen is also going to benefit the bacteria involved in nitrogen cycling (which are mostly aerobes). Still, I don't like the leave it running too long, since the fry aren't yet strong enough swimmers to deal with the water currents set up by the filter.
So while still water is likely to reduce the energy demands of the fry, it also reduces the oxygen content of the water (and possibly the ammonia and nitrite concentrations). I don't know if it's a net benefit or cost. On the other hand, the Ludwigia seem happy with the stillness and the falling water levels. Several stems have emerged above the water level, and at least one of them has flowered. The breeding aquarium has taken on something of a pond appearance, which I really like.
Monday, 16 April 2007
A few hours later there were still a number of them left, but my this morning I couldn't see anything left of the second batch of baby Macropodus.
Saturday, 14 April 2007
The nest is full of fry. Not sure what happens next - they are supposed to be free swimming by day 3. I'm not sure what happens then - if he will still protect them, and if he will be able to protect them.
Friday, 13 April 2007
While the male seems to have a good grasp on his role, the female seems a bit less sure what to do. Unlike him, she is still eating - may be eating eggs and fry as well (I have seen her gather up errant fry, but I haven't seen her return anything to the nest). In addition, the male chases her when she gets too close to the nest. On the other hand, she is doing a good job chasing everyone else away from the nest. She seems to have an especial dislike for the angels - she goes to the far end of the tank to find angels to chase.
I noticed that the fry tend to attach to surfaces - not just bubbles, but also the glass or plant stems. I suppose there's survival value in that - they are less visible if they attack to vegetation.
Thursday, 12 April 2007
The female, on the other hand, is behaving oddly - she has taken to chasing the angels, which is interesting, since the larger angels are about her size. She ignores the smaller fish, but seems determined to keep the angels out of the portion of the tank that includes the nest. The male, on the other hand, seems to ignore the angels pretty much, but chases any platies that get too close.
A shot of the nest through the side of the tank (and a nice shot of the camera, reflecting off the glass)
These are taken from above. The eggs are visible in the lower picture.
And here's the male Macropodus, sitting below the nest. No longer in breeding colours, he seems pretty washed out.
Well...we'll see what happens.
Update: Turns out that events had overtaken me - he already has a nest full of eggs. They must have mated last night. Surprisingly, he seems to have done a pretty good job of defending the nest - it hasn't turned into a free-for-all feeding place.
Tuesday, 10 April 2007
The fry have grown considerably, but they are still very small. The fry which congregate in the Elodea look like a fruit flies. I have subdivided the fry into several groups (the Elodea group, the open-water group, the heater group) but it's probably more a matter of my perception than it actually is of any subdivision among them.
It's quite interesting to watch the fry hunt brine shrimp. Some of them appear to be more experienced hunters by now - they see the brine shrimp, head straight for them, and gobble them up. Others seem less sure what to do - they see them, follow them for a while, and then pounce. It may be an experience thing - when I first added the brine shrimp all the fry seemed uncertain - they ignored them first, then followed them for a while, and then finally pounced (feeding is always a jerky motion for them).
I'm a little concerned about water quality in the breeding tank. I have had the filter off for over a week now, so both oxygen levels and biofiltration are likely to be lagging. I'm wondering if I should buy a pump and air stone, so that they get the agitation without the intake issues. I suppose I could also find some fine fabric to put over the intake of the filter - switching on the filter would radically alter the fry's world. I also need to think about some other food options - egg yolk, or finely ground fish food - something to supplement brine shrimp (since I really don't have a high-throughput system, or the means to set one up).
Monday, 9 April 2007
I initially got the impression that ich was a water quality issue - that the causal organisms were normally present in aquaria, but only became a problem when fish were otherwise stressed. That proved to be a misconception - Ichthyophthirius multifiliis appears to lack a dormant life stage, so it can only be transmitted by infected fish or by plants (or other substrate) upon which the tomont has encysted. The infectious trophont is the sensitive stage - this is the one that can be affected by medications, and it appears that the infectious trophont stage can't survive more than a couple days outside of the body. Hence the suggestion that they best way to "clean" a tank is to leave it fish-free for a few days. Of course this doesn't answer the "Typhoid Mary" question - are there outwardly healthy carriers of the disease? To some extent this is true - since the parasites tend to infect the gills, it's possible to have an infected fish that lacks the characteristic white spots. But these fish will still only remain infected until the trophonts mature and drop off. Are there dormant infections - ones that will remain in the trophont stage until the fish is stressed?
Sunday, 8 April 2007
Ich is a disease caused by a parasitic ciliate. I got the impression initially that it was a disease of low water quality - that the organism was usually present in aquaria, but only stressed fish suffered actual outbreaks. Turns out that bit of conventional wisdom is false - it's an obligate parasite, so any introduction needs to come either with living fish or live plants. I hadn't thought of quarantining plants (well, slightly, but not to any great extent).
So how did I get it? The outbreak seems to be confined to the platies, but it's almost impossible that they are the cause. Most of my platies were born in this tank - they were the first fish I got. So the true culprits must either be plants (which are, after all, my most recent purchases) or an asymptomatic fish ("asymptomatic" in the sense that I can't see the symptoms, although they could easily be on the gills). I've had my newest fish (the Otocinclus and the Kuhli loaches) for two and a half weeks, so they could be the culprits, as could the new plants.
Friday, 6 April 2007
I'm guessing that a "Trinidad Pleco" is a Teta (Hypostomus robinii). Unfortunately, there were none in the tank at the time.
Update: According to PlanetCatfish, a Trinidad Pleco is Pterygoplichthys punctatus, a Brazilian species with no apparent links to Trinidad (at least not Trinidad and Tobago).
Wednesday, 4 April 2007
The fry in the breeding box seem to be doing pretty well without parental care. Most of the eggs hatched - the biggest risk is probably drowning, but there's enough floating vegetation in the box to keep them near the surface. Water quality is another issue - the fry food, which was probably a bad idea to begin with, just sinks to the bottom and (presumably) rots. While the community tank, with its filter still on, is likely to have better overall water quality than the other tank (where I had to switch the filter off), the breeding box creates a pool of stagnant water. Well, these are fish that evolved in stagnant pools of water, so hopefully they can handle things like that.
Food is another concern. The community tank is starting to get "furry" - there's a lot of epiphyllic algae on the leaves and stems of th plants. The plants in the breeding box are likely to be a good source of food for the fry. The breeding tank is never and cleaner, with large areas of open water. I'm less sure about the food supply in that tank. It's also hard to get the fry food anywhere near the fry. I've been adding my "infusoria", but I'm by no means certain about the sort of growth I'm getting in those containers. The weather has also taken a cold turn, and the bottles were sitting in an open window, so that's likely to have slowed growth of both bacteria and protists last night.
Tuesday, 3 April 2007
It would have been fun to let them breed in the big tank and let the babies fend for themselves. I think I like the platies more because they were able to grow up "by their wits", to survive in what was at the time a much less heavily planted tank. I like seeing a few bold fry emerging from the plants. Raising fry in a dedicated breeding tank is a bit less exciting, although the idea is still appealing. Granted, it's a bit presumptive to talk about raising fry when, thus far, you don't have any clue what you are doing or how you are going to keep them fed.
Amazingly, the breeding box has babies as well - despite the obviously inferior conditions and lack of parental care (and a nest) there are also fry swimming around in there.
Monday, 2 April 2007
I'm really glad they bred, and I'm looking forward to the eggs hatching, but I really don't know what I would do with a crop of baby Macropodus. Not that I really have to worry about that - getting the fish to spawn is the easy part - raising the fry is far more difficult.