April 2018 Extinction Event

The April 2018 Extinction Event, also known as the TE-LE Extinction Event or the TE-LE Boundary, was an extinction event that resulted in the extinction of the Black Neon Tetras, Green Neon Tetras, Glowlight Tetras and German Blue Ram, and the subsequent return of guppies to power.

History
Prior to the event, Tetras were the dominant fish in The Tank and were the ruling class. Before this, guppies were the ruling class and had been since The Tank's conception. Black Neons were the rulers, the Green Neons were the nobility and the Glowlights were the warriors. Life was peaceful but very restrictive for most other species, especially the guppies, as they occupied the whole of the middle column. Towards the end of the Tetra rule, they were starting to fall out of favour with the other inhabitants for said restrictiveness and that the guppies were mostly unable to reproduce under their rule, since the fry were always eaten. This put guppies under the threat of total extinction as if they contracted any kind of disease, it would be game over.

Event
The event started with two new fish being introduced in their bag: a male guppy, and a male platy. Soon after, the tetras were targeted by a net, and slowly but surely they were all caught. The black neons lasted the longest, but they too were caught. What happened after that is unknown, but one thing was for sure: they had just gone extinct in an extinction event not to dissimilar to the November 2017 Extinction Event.

Effects
The first and most immediate effect was that the Tetras were no longer the ruling class, but neither were guppies at this stage. The title actually went to the Cory Catfish as they were now the most numerous species. This did not last long though, as new guppies and platies were soon introduced and they formed a 'Livebearer rule' together. Even so, the guppies did not need to to form a majority.

Life under the livebearer rule is much less restrictive. Minority species are for the most part left to mind their own business.

The other effect is that the livebearers can now reproduce.

A long term effect is that the shrimp are now able to reproduce and have their offspring survive. This event eventually lead to the July 2018 Shrimp Explosion.