'There are 34,000 different types of fishes in the world. Some have unfolded unique ways to raise the younglings—way unconventional than other higher life forms.' Observing a cichlid pair tending their new-borns in one of my aquaria, I was muttering the facts. Shortly afterward, I came up with the second instalment of the Parental Care series. This time, it is all about fishes.
But, a spin-off struck me well in the very beginning. Thanks to Hans Christian Andersen and Disney, the Little Mermaid appeared in my mind as soon as I had started writing. Not paying much heed to the elders, Ariel hopped on hapless life events. And, that didn't set an ideal notion of good parenting—for none. Tragic as the end may sound, in contrast, the Little Mermaid never portrays the evolutionary triumph of fishes in parental care.
Instead, the fish pair I am keeping for months does the job well. I was in breathing distance, just a barrier of glass between us. Unaware of anything other than safety of the fries, the bonded duo was constant in guarding the nest. Their perseverance kept me stuck to the developing of the idea. As I delved deeper into this, overwhelming waves of examples begun to overrun my neurons.
So, without any further ado, let's have a look the fish parents, caring and intelligent and bold and fearless—all in a single package!
Safety is in safe nest sites
It is said by biologists that choosing and making nests is the most primitive and the foremost step of parenting. Well, fishes have mastered this like any other. From stinging surrogate animal to snail shell to mud burrow to floating bubble nest to cleaned flat rock surface out in the open, fish houses are bewildering!
The lungfish scoops out a hallow depression in the mud of swamp, rich in aquatic weeds and grasses, which afford protection. The bullhead catfishes may well take a submerged rat-hole for egg-laying! The air-breathing gouramies prefer to making floating mat of sticky air bubbles. The clownfishes resort to deadly anemone tentacles. Evolution gifted them with protection, but, anemones ain't no easy affair for others!
The second step of nest-making requires a watchman. The fishes adapt this well. Often in pair, the brood guard the eggs and fry from all danger. The strategy can be species-specific. Yet, the rule is simple. While there are baby fishes in home, no trespassing is allowed! The cichlids, the group where the very known tilapia belongs to, are some of the top-ranked parent guards. Size does not make a count to them. Per say, the pair I am keeping —convict cichlid, a meso-american species—took over the entire 35-gallon tank. Introducing any other fish during breeding, regardless of size and temperament, becomes a big no-no!
Large pelagic hunters, who don't make any nest, too, are well-known for guarding. Snakeheads, as you may call them Shoal and Gojar can put up a spectacular show in monsoon. While parents swim at slow pace, fries—hundreds of them—trails rhythmically as if cloud swirled in a breeze!
Momma's mouth—a refugium
For the fish world, scientists have coined a term – mouth brooding. This means there are some fishes which are known to carry young in their mouth. When the fries sense any danger approaching, they see one safe house—mouth of the brood. Many species do this as last resorts. Many others are used to keep the eggs just after being laid. Arowana and the African lake cichlids are the best in doing this. Fries in this sort of breeding strategy are generally small in number, leaving the mouth-refugium only when they attain a certain size. You may begin wondering—do the parents eat anything in these times? Your guess is right. The obligate mouth-breeders do not take anything.
The kangaroo under water
We know that kangaroos carry their natals in pouch. Well, the gill-breathers carry the tricks up under their sleeve (or, should I say in pouch?). Male of sea-horses, sea-dragons and pipe-fishes take the eggs in belly pouch and carry them until they hatch. There is one catfish from Brazil, the Brazilian catfish, where in females, the belly becomes spongy and sticky. The eggs after being laid stick to the cup-like belly-depressions of the mother. Thus, they stay always under watch!
Here comes the aquatic cuckoo
No different to what cuckoo does, the cuckoo catfish mimicks the same. The fish lays egg in other fish's nests. Native to Africa, they target nesting and mouth-brooding cichlids. As soon as the male creates a diversion, the female lays eggs while the cichlid parents are busy in warding off. The catfish fries (only one or two) get into mouth-shelter after hatching. There they sustain on cichlid fries. And, one day after devouring all fries, when the poor cichlid host can no longer hold them in mouth, they emerge.
Story of the yearlings
Many killifishes have a lifespan of one year or so. They do the act of breeding very differently—unique than anyone can imagine. These fishes live in seasonal pool meaning when they will be gone their temporary pool will follow likewise. But, that cannot stop life! The killis find a way. They bury their egg under substrate. The eggs themselves can tolerate moisture to the least amount. The extent is so extreme that these eggs are traded as plant seeds. Order one pack on Amazon, get them into your tank and be sure to have killifishes!
The more the merrier
At this moment, it is very normal to see a reader multi-tasking—having a platter of mushy hilsa eggs and thinking of the strategy the fish might take in breeding. Hilsa is built for speed. There is no room for care or anything sluggish and soft. Yet, they do thrive. Shads, tunas and many other open-water fast swimmers lay millions of eggs. Out of millions, merely 1% do reach adulthood. A pretty handsome figure in a breeding attempt, and a victory for the species. So, the strength here lies in number!
So, fishes are not simple and primitive as they are seen–vulnerable out of water and smelly to many. Fishes have their own ways of wonder. Try petting a cichlid pair or order a pack of killifish egg. May be try watching a snakehead couple with a swerving shoal of fingerlings. You will get the essence.