RD/KP24-JP023 サイボーグ・ドルフィン Cyborg Dolphin [Mech Dolphin]
Level 2 WATER Fish Effect Monster
ATK 500
DEF 400
【REQUIREMENT】 If there is a face-up Level 7 or lower WATER Fish Ritual Monster on your field.
【EFFECT】 Choose 1 card on your opponent’s field and return it to the hand. You cannot attack with monsters for the rest of the turn, except Fish monsters.

Note: This is White Dolphin remade with mechanical parts, possibly inspired by Mech Bass.

RD/KP24-JP024 サイボーグ・ナイル Cyborg Nile [Mech Misairuzame]
Level 5 WATER Fish Effect Monster
ATK 1400
DEF 1600
【REQUIREMENT】 None
【CONTINUOUS EFFECT】 During the Battle Phase, face-up Fish monsters on your field gain 400 ATK x [The number of monsters on your field]. Your “Fortress Whale” can attack directly.

Note: This is Misairuzame (Nile in Japan) remade with mechanical parts. Likely to go with Mech Dolphin, both possibly inspired by Mech Bass.

As a wider note:

• the Japanese name of “Mech Bass” is サイボーグ・バス, which translates to “Cyborg Bass”. These are both Cyborg monsters.
• One of these monsters is wearing the armor of “Mech Bass”

Therefore with that in mind, both these monsters are being translated as “Mech [X]”

RD/KP24-JP027 シュライン・リンコス Shrine Rhynchus
Level 4 WATER Fish Effect Monster
ATK 1000
DEF 1300
【REQUIREMENT】 During the turn this card was Normal Summoned.
【EFFECT】 Send the top 2 cards of your Deck to the Graveyard. Then, you can choose 1 Ritual Spell in your Graveyard and Set it to your Spell & Trap Zone. You cannot attack with monsters for the rest of the turn, except Fish monsters.

Note: This card most likely takes its name from its name from the rhynchus in Oxyrhynchus (Greek for Sharp-nosed), a city in Egypt that worshiped the Medjed, a type of Elephant Fish that in Egyptian Mythology ate the genitals of Osiris, preventing his full resurrection, resulting in him becoming the God of the Dead.

RD/KP24-JP041 要塞クジラ Yousai Kujira (Fortress Whale)
Level 7 WATER Fish Ritual Monster
ATK 2400
DEF 2200

RD/KP24-JP057 要塞クジラの誓い Yousai Kujira no Chikai (Fortress Whale Oath)
Ritual Spell Card
【REQUIREMENT】 None
【EFFECT】 Ritual Summon “Fortress Whale” by sending monsters in your hand and/or on your field to the Graveyard whose combined levels total 7 or more as material. (You cannot use more monsters than necessary as material.)

Source: YU-GI-OH!.jp