Cover - USD ($)	12 Months Ended
	Sep. 30, 2025	Dec. 29, 2025	Mar. 31, 2025
Cover [Abstract]
Entity Registrant Name	TANICO INC.
Entity Central Index Key	0001895939
Document Type	10-K
Amendment Flag	false
Entity Voluntary Filers	No
Current Fiscal Year End Date	--09-30
Entity Well Known Seasoned Issuer	No
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Current Reporting Status	Yes
Document Period End Date	Sep. 30, 2025
Entity Filer Category	Non-accelerated Filer
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2025
Entity Ex Transition Period	false
Entity Common Stock Shares Outstanding		7,825,000
Entity Public Float			$ 0
Document Annual Report	true
Document Transition Report	false
Document Fin Stmt Error Correction Flag	false
Entity File Number	333-261643
Entity Incorporation State Country Code	NV
Entity Tax Identification Number	37-2002382
Entity Address Address Line 1	387 Whitby Shores Greenway
Entity Address City Or Town	Whitby
Entity Address State Or Province	ON
Entity Address Country	CA
Entity Address Postal Zip Code	L1N 9R6
City Area Code	775
Auditor Name	JLKZ CPA LLP
Auditor Location	Flushing, New York
Auditor Firm Id	6519
Local Phone Number	404-0333
Entity Interactive Data Current	Yes
Security 12b Title	Common