Otto

Otto has been discontinued and can no longer be played online. If you're looking for a similar game, you might like these other fish-themed slots.

Otto was an older 36Gaming underwater video slot built around a bright coral reef, five reels and 25 adjustable paylines. It offered wilds, scatters, free spins and a separate bonus game, but its RTP was never published.

Provider: 36Gaming
Paylines: 25
Reels: 5
Coins (Min): 0.01
Coins (Max): 0.20
Coins/Line (Min): 1
Coins/Line (Max): 2

Progressive: No
Wild Symbol: Yes
Scatter Symbol: Yes
Bonus Game: Yes
Free Spins: Yes
Autoplay: Yes
Multiplier: No

Otto took players under the sea. The reels sat beneath the surface on a bright coral reef , with bubbles, blue watery colours and a bubbly OTTO design. It had the cheerful look of an older casual slot.

Classic Reef Layout and Simple Betting

Developed by 36Gaming , Otto was an older video slot reviewed around 2017. The game is now discontinued, so you cannot treat this as a current-play recommendation. Still, it is worth a quick look for players who like classic five-reel layouts and straightforward features. The RTP was never published, which is the first thing I would have wanted to know before staking real money. Otto used five reels and three rows, with 25 displayed paylines. You could adjust the lines and choose one or two coins per line. Coin values ran from 0.01 to 0.20, meaning a full 25-line spin ranged from 0.25 to 10.00. That gave careful players room to keep stakes modest, while higher settings made each spin move faster through the balance. The symbol set stayed firmly underwater. An orange and white clownfish acted as the wild, replacing other symbols but not the scatter. You also saw a sunglasses-wearing starfish, a googly-eyed crab, a shark, an emperor angelfish and A, K and J card ranks decorated with little fish. The presentation was bright and playful, though the mechanics were deliberately familiar.

Otto slot base game with clownfish wilds, a pearl oyster scatter and sea creatures on a coral reef

The Otto base game: five reels, 25 lines and a clownfish wild.

Wilds, Scatters and the Bonus Features

The pearl inside an oyster shell was Otto's scatter. Three or more scatters triggered the free spins feature, giving the game its main chance to break away from ordinary base-game play. The free spins were the feature most players hoped to see, as they offered extra rounds without touching the balance.

There was also a separate bonus game, triggered by three or more bonus symbols. That distinction matters because it was not simply another name for the free spins round. Autoplay and a Max Bet button were available as well. There was no progressive jackpot, no bonus buy and no evidence of cascades or other modern add-ons. Otto kept things old-school.

What Players Needed to Watch

The biggest drawback was not the underwater theme . It was the missing maths information. Otto's RTP was never published, so you could not compare its long-term return with better-documented games. I would not guess at a volatility rating or max win either, because neither was reliably provided. Those gaps matter more than a pretty reef when you are deciding how long a bankroll might last. The other practical issue is simple: Otto has been discontinued and can no longer be played online. That makes this a historical review rather than a recommendation to search for an active casino version. If you remember it from around 2017, the appeal was its clean layout and uncomplicated features. For today's players, the lesson is to check RTP, rules and availability before getting attached to the artwork.

Summary

Otto was a likeable older slot with a clear underwater identity, a 5x3 layout and 25 paylines. The clownfish wild, oyster scatter, free spins and separate bonus game supplied enough variety without turning the rules into a puzzle.

But the missing RTP weakens the review, and the game's discontinuation settles the practical question. Otto is best remembered as a straightforward 36Gaming reef slot, not treated as a game you can currently play or assess against today's better-documented releases.